Method and apparatus for configuring subband aggregation in nr carrier in wireless communication system

ABSTRACT

A method and apparatus for configuring a data subband in a wireless communication system is provided. A user equipment (UE) receives an indication of a data subband from a network, configures at least one data subband according to the indication, and performs communication with the network via the at least one data subband. One data subband consists of contiguous or non-contiguous physical resource blocks (PRBs).

TECHNICAL FIELD

The present invention relates to wireless communications, and moreparticularly, to a method and apparatus for configuring subbandaggregation in a new radio access technology (NR) carrier in a wirelesscommunication system.

BACKGROUND ART

3rd generation partnership project (3GPP) long-term evolution (LTE) is atechnology for enabling high-speed packet communications. Many schemeshave been proposed for the LTE objective including those that aim toreduce user and provider costs, improve service quality, and expand andimprove coverage and system capacity. The 3GPP LTE requires reduced costper bit, increased service availability, flexible use of a frequencyband, a simple structure, an open interface, and adequate powerconsumption of a terminal as an upper-level requirement.

As more and more communication devices require more communicationcapacity, there is a need for improved mobile broadband communicationover existing radio access technology. Also, massive machine typecommunications (MTC), which provides various services by connecting manydevices and objects, is one of the major issues to be considered in thenext generation communication. In addition, communication system designconsidering reliability/latency sensitive service/UE is being discussed.The introduction of next generation radio access technology consideringenhanced mobile broadband communication (eMBB), massive MTC (mMTC),ultra-reliable and low latency communication (URLLC) is discussed. Thisnew technology may be called new radio access technology (new RAT or NR)for convenience.

In NR, analog beamforming may be introduced. In case of millimeter wave(mmW), the wavelength is shortened so that a plurality of antennas canbe installed in the same area. For example, in the 30 GHz band, a totalof 100 antenna elements can be installed in a 2-dimension array of 0.5lambda (wavelength) intervals on a panel of 5 by 5 cm with a wavelengthof 1 cm. Therefore, in mmW, multiple antenna elements can be used toincrease the beamforming gain to increase the coverage or increase thethroughput.

In this case, if a transceiver unit (TXRU) is provided so thattransmission power and phase can be adjusted for each antenna element,independent beamforming is possible for each frequency resource.However, installing a TXRU on all 100 antenna elements has a problem interms of cost effectiveness. Therefore, a method of mapping a pluralityof antenna elements to one TXRU and adjusting the direction of a beamusing an analog phase shifter is considered. This analog beamformingmethod has a disadvantage that it cannot perform frequency selectivebeaming because it can make only one beam direction in all bands.

A hybrid beamforming with B TXRUs, which is an intermediate form ofdigital beamforming and analog beamforming, and fewer than Q antennaelements, can be considered. In this case, although there is adifference depending on the connection method of the B TXRU and Qantenna elements, the direction of the beam that can be simultaneouslytransmitted is limited to B or less.

For operating NR efficiently, various schemes have been discussed.

DISCLOSURE OF INVENTION Technical Problem

The present invention provides a method and apparatus for configuringsubband aggregation in a new radio access technology (NR) carrier in awireless communication system. The present invention proposes handlingwideband carrier where different user equipments (UEs) may supportdifferent UE system bandwidth and also the configured bandwidth ischanged for UE power saving and efficient resource management.

Solution to Problem

In an aspect, a method for configuring a data subband by a userequipment (UE) in a wireless communication system is provided. Themethod includes receiving an indication of a data subband from anetwork, configuring at least one data subband according to theindication, and performing communication with the network via the atleast one data subband. One data subband consists of contiguous ornon-contiguous physical resource blocks (PRBs).

In another aspect, a user equipment (UE) in a wireless communicationsystem is provided. The UE includes a memory, a transceiver, and aprocessor, operably coupled to the memory and the transceiver, thatcontrols the transceiver to receive an indication of a data subband froma network, configures at least one data subband according to theindication, and controls the transceiver to perform communication withthe network via the at least one data subband. One data subband consistsof contiguous or non-contiguous physical resource blocks (PRBs).

Advantageous Effects of Invention

Efficient communication between UE and network and resource managementcan be enabled by using subbands in a NR carrier.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a 3GPP LTE system.

FIG. 2 shows structure of a radio frame of 3GPP LTE.

FIG. 3 shows a resource grid for one downlink slot.

FIG. 4 shows an example of subframe type for NR.

FIG. 5 shows an example of different system bandwidth between networkand UE in a NR carrier.

FIG. 6 shows an example of carrier bonding.

FIG. 7 shows an example of RB indexing according to an embodiment of thepresent invention.

FIG. 8 shows an example of configuration of different search space perUE according to an embodiment of the present invention.

FIG. 9 shows an example of handling anchor subband and other subband forUE-specific bandwidth separately according to an embodiment of thepresent invention.

FIG. 10 shows examples of different UE-specific bandwidth optionsaccording to an embodiment of the present invention.

FIG. 11 shows an example of UE-specific supported bandwidth according toan embodiment of the present invention.

FIG. 12 shows an example of individual RB indexing according to anembodiment of the present invention.

FIG. 13 shows examples of dynamic bandwidth adaptation via data subbandaggregation according to an embodiment of the present invention.

FIG. 14 shows examples of bandwidth adaptation via data subbandaggregation with multiple RF according to an embodiment of the presentinvention.

FIG. 15 shows an example of resource allocation in a nested manneraccording to an embodiment of the present invention.

FIG. 16 shows an example of different handling options for widebandspectrum with narrowband UE RFs according to an embodiment of thepresent invention.

FIG. 17 shows an example of interference in case of small bandwidthtransmission.

FIG. 18 shows an example of interference in case of multiple RFs.

FIG. 19 shows an example of overlaid structure according to anembodiment of the present invention.

FIG. 20 shows an example of option 1 for RRM handling in widebandaccording to an embodiment of the present invention.

FIG. 21 shows an example of option 2 for RRM handling in widebandaccording to an embodiment of the present invention.

FIG. 22 shows an example of option 3 for RRM handling in widebandaccording to an embodiment of the present invention.

FIG. 23 shows an example of different RRM bandwidth options according toan embodiment of the present invention.

FIG. 24 shows a method for configuring a data subband by a UE accordingto an embodiment of the present invention.

FIG. 25 shows a wireless communication system to implement an embodimentof the present invention.

MODE FOR THE INVENTION

FIG. 1 shows a 3GPP LTE system. The 3rd generation partnership project(3GPP) long-term evolution (LTE) system 10 includes at least one eNodeB(eNB) 11. Respective eNBs 11 provide a communication service toparticular geographical areas 15 a, 15 b, and 15 c (which are generallycalled cells). Each cell may be divided into a plurality of areas (whichare called sectors). A user equipment (UE) 12 may be fixed or mobile andmay be referred to by other names such as mobile station (MS), mobileterminal (MT), user terminal (UT), subscriber station (SS), wirelessdevice, personal digital assistant (PDA), wireless modem, handhelddevice. The eNB 11 generally refers to a fixed station that communicateswith the UE 12 and may be called by other names such as base station(BS), base transceiver system (BTS), access point (AP), etc.

In general, a UE belongs to one cell, and the cell to which a UE belongsis called a serving cell. An eNB providing a communication service tothe serving cell is called a serving eNB. The wireless communicationsystem is a cellular system, so a different cell adjacent to the servingcell exists. The different cell adjacent to the serving cell is called aneighbor cell. An eNB providing a communication service to the neighborcell is called a neighbor eNB. The serving cell and the neighbor cellare relatively determined based on a UE.

This technique can be used for DL or UL. In general, DL refers tocommunication from the eNB 11 to the UE 12, and UL refers tocommunication from the UE 12 to the eNB 11. In DL, a transmitter may bepart of the eNB 11 and a receiver may be part of the UE 12. In UL, atransmitter may be part of the UE 12 and a receiver may be part of theeNB 11.

The wireless communication system may be any one of a multiple-inputmultiple-output (MIMO) system, a multiple-input single-output (MISO)system, a single-input single-output (SISO) system, and a single-inputmultiple-output (SIMO) system. The MIMO system uses a plurality oftransmission antennas and a plurality of reception antennas. The MISOsystem uses a plurality of transmission antennas and a single receptionantenna. The SISO system uses a single transmission antenna and a singlereception antenna. The SIMO system uses a single transmission antennaand a plurality of reception antennas. Hereinafter, a transmissionantenna refers to a physical or logical antenna used for transmitting asignal or a stream, and a reception antenna refers to a physical orlogical antenna used for receiving a signal or a stream.

FIG. 2 shows structure of a radio frame of 3GPP LTE. Referring to FIG.2, a radio frame includes 10 subframes. A subframe includes two slots intime domain. A time for transmitting one transport block by higher layerto physical layer (generally over one subframe) is defined as atransmission time interval (TTI). For example, one subframe may have alength of 1 ms, and one slot may have a length of 0.5 ms. One slotincludes a plurality of orthogonal frequency division multiplexing(OFDM) symbols in time domain. Since the 3GPP LTE uses the OFDMA in theDL, the OFDM symbol is for representing one symbol period. The OFDMsymbols may be called by other names depending on a multiple-accessscheme. For example, when SC-FDMA is in use as a UL multi-access scheme,the OFDM symbols may be called SC-FDMA symbols. A resource block (RB) isa resource allocation unit, and includes a plurality of contiguoussubcarriers in one slot. The structure of the radio frame is shown forexemplary purposes only. Thus, the number of subframes included in theradio frame or the number of slots included in the subframe or thenumber of OFDM symbols included in the slot may be modified in variousmanners.

The wireless communication system may be divided into a frequencydivision duplex (FDD) scheme and a time division duplex (TDD) scheme.According to the FDD scheme, UL transmission and DL transmission aremade at different frequency bands. According to the TDD scheme, ULtransmission and DL transmission are made during different periods oftime at the same frequency band. A channel response of the TDD scheme issubstantially reciprocal. This means that a DL channel response and a ULchannel response are almost the same in a given frequency band. Thus,the TDD-based wireless communication system is advantageous in that theDL channel response can be obtained from the UL channel response. In theTDD scheme, the entire frequency band is time-divided for UL and DLtransmissions, so a DL transmission by the eNB and a UL transmission bythe UE cannot be simultaneously performed. In a TDD system in which a ULtransmission and a DL transmission are discriminated in units ofsubframes, the UL transmission and the DL transmission are performed indifferent subframes. In a TDD system, to allow fast switching between DLand UL, UL and DL transmission may be performed within a samesubframe/slot in time division multiplexing (TDM)/frequency divisionmultiplexing (FDM) manner.

FIG. 3 shows a resource grid for one downlink slot. Referring to FIG. 3,a DL slot includes a plurality of OFDM symbols in time domain. It isdescribed herein that one DL slot includes 7 OFDM symbols, and one RBincludes 12 subcarriers in frequency domain as an example. However, thepresent invention is not limited thereto. Each element on the resourcegrid is referred to as a resource element (RE). One RB includes 12×7 or12×14 resource elements. The number N_(DL) of RBs included in the DLslot depends on a DL transmit bandwidth. The structure of a UL slot maybe same as that of the DL slot. The number of OFDM symbols and thenumber of subcarriers may vary depending on the length of a CP,frequency spacing, etc. For example, in case of a normal cyclic prefix(CP), the number of OFDM symbols is 7 or 14, and in case of an extendedCP, the number of OFDM symbols is 6 or 12. One of 128, 256, 512, 1024,1536, 2048, 4096 and 8192 may be selectively used as the number ofsubcarriers in one OFDM symbol.

5th generation mobile networks or 5th generation wireless systems,abbreviated 5G, are the proposed next telecommunications standardsbeyond the current 4G LTE/international mobile telecommunications(IMT)-dvanced standards. 5G includes both new radio access technology(new RAT or NR) and LTE evolution. Hereinafter, among 5G, NR will befocused. 5G planning aims at higher capacity than current 4G LTE,allowing a higher density of mobile broadband users, and supportingdevice-to-device, ultra-reliable, and massive machine communications. 5Gresearch and development also aims at lower latency than 4G equipmentand lower battery consumption, for better implementation of the Internetof things.

NR may use the OFDM transmission scheme or a similar transmissionscheme. NR may follow the existing LTE/LTE-A numerology, or may followthe different numerology from the existing LTE/LTE-A numerology. NR mayhave a larger system bandwidth (e.g. 100 MHz). Or, one cell may supportmultiple numerologies in NR. That is, UEs operating in differentnumerologies may coexist within one cell in NR.

It is expected that different frame structure may be necessary for NR.Particularly, different frame structure in which UL and DL may bepresent in every subframe or may change very frequently in the samecarrier may be necessary for NR. Different application may requiredifferent minimum size of DL or UL portions to support different latencyand coverage requirements. For example, massive machine-typecommunication (mMTC) for high coverage case may require relatively longDL and UL portion so that one transmission can be successfullytransmitted. Furthermore, due to different requirement onsynchronization and tracking accuracy requirements, different subcarrierspacing and/or different CP length may be considered. In this sense, itis necessary to consider mechanisms to allow different frame structurescoexisting in the same carrier and be operated by the same cell/eNB.

In NR, utilizing a subframe in which downlink and uplink are containedmay be considered. This scheme may be applied for paired spectrum andunpaired spectrum. The paired spectrum means that one carrier consistsof two carriers. For example, in the paired spectrum, the one carriermay include a DL carrier and an UL carrier, which are paired with eachother. In the paired spectrum, communication, such as DL, UL,device-to-device communication, and/or relay communication, may beperformed by utilizing the paired spectrum. The unpaired spectrum meansthat that one carrier consists of only one carrier, like the current 4GLTE. In the unpaired spectrum, communication, such as DL, UL,device-to-device communication, and/or relay communication, may beperformed in the unpaired spectrum.

Further, in NR, the following subframe types may be considered tosupport the paired spectrum and the unpaired spectrum mentioned above.

(1) Subframes including DL control and DL data

(2) Subframes including DL control, DL data, and UL control

(3) Subframes including DL control and UL data

(4) Subframes including DL control, UL data, and UL control

(5) Subframes including access signals or random access signals or otherpurposes.

(6) Subframes including both DL/UL and all UL signals.

However, the subframe types listed above are only exemplary, and othersubframe types may also be considered.

FIG. 4 shows an example of subframe type for NR. The subframe shown inFIG. 4 may be used in TDD system of NR, in order to minimize latency ofdata transmission. Referring to FIG. 4, the subframe contains 14 symbolsin one TTI, like the current subframe. However, the subframe includes DLcontrol channel in the first symbol, and UL control channel in the lastsymbol. A region for DL control channel indicates a transmission area ofa physical downlink control channel (PDCCH) for Downlink controlinformation (DCI) transmission, and a region for UL control channelindicates a transmission area of a physical uplink control channel(PUCCH) for uplink control information (UCI) transmission. Here, thecontrol information transmitted by the eNB to the UE through the DCI mayinclude information on the cell configuration that the UE should know,DL specific information such as DL scheduling, and UL specificinformation such as UL grant. Also, the control information transmittedby the UE to the eNB through the UCI may include a hybrid automaticrepeat request (HARQ) acknowledgement/non-acknowledgement (ACK/NACK)report for the DL data, a channel state information (CSI) report on theDL channel status, and a scheduling request (SR). The remaining symbolsmay be used for DL data transmission (e.g. physical downlink sharedchannel (PDCCH)) or for UL data transmission (e.g. physical uplinkshared channel (PUCCH)).

According to this subframe structure, DL transmission and ULtransmission may sequentially proceed in one subframe. Accordingly, DLdata may be transmitted in the subframe, and ULacknowledgement/non-acknowledgement (ACK/NACK) may also be received inthe subframe. In this manner, the subframe shown in FIG. 4 may bereferred to as self-contained subframe. As a result, it may take lesstime to retransmit data when a data transmission error occurs, therebyminimizing the latency of final data transmission. In the self-containedsubframe structure, a time gap may be required for the transitionprocess from the transmission mode to the reception mode or from thereception mode to the transmission mode. For this purpose, some OFDMsymbols at the time of switching from DL to UL in the subframe structuremay be set to the guard period (GP).

In NR, wideband may be used if the network supports. Further in NR, bothnetwork and UE may have different bandwidths to be supported. In thiscase, it may need to be clarified how the network and UE operatetransmission and reception.

FIG. 5 shows an example of different system bandwidth between networkand UE in a NR carrier. The carrier bandwidth that the network supportsmay be a system bandwidth. The UE supported bandwidth may be equal tothe system bandwidth or different from the system bandwidth (may benarrower or wider than the system bandwidth). FIG. 5-(a) shows a casethat the system bandwidth is same as the UE supported bandwidth. FIG.5-(b) shows a case that the system bandwidth is different from the UEsupported bandwidth, i.e. the system bandwidth is wider than the UEsupported bandwidth. FIG. 5-(c) shows a case that the system bandwidthis different from the UE supported bandwidth, i.e. the system bandwidthis wider than the UE supported bandwidth. But contrary to FIG. 5-(b),the UE may support wide bandwidth with multiple radio frequency (RF)components. A baseband component may be shared among multiple RFscomponents, or separate baseband component may be dedicated per RFcomponent. Though it may depend on UE capability, in the presentinvention, it is assumed that baseband component/capability may beshared among multiple RF components.

FIG. 6 shows an example of carrier bonding. Depending on necessarysystem bandwidth, the network may bond multiple NR carriers. If multipleNR carriers are bonded and formed as one NR carrier, the systembandwidth may be changed. The center frequency may also be changed.Though, the direct current (DC) center may or may not be changeddepending on network operation. If the DC center is changed, it may beindicated to UEs so that DC carrier can be correctly handled.

In these scenarios, how to assign UE-system bandwidth to UEs may followby at least one of options below.

(1) A NR carrier may be divided into a set of minimum-subband (M-SB). Asubset of M-SBs may be configured to UE via UE-specific signaling.

(2) A UE may be configured with start and end frequency location of theUE-specific system bandwidth via UE-specific signaling.

(3) A NR carrier may be divided into a set of physical resource blocks(PRBs), and a set of PRBs may be configured to UE via UE-specificsignaling.

(4) A NR carrier may be divided into a set of PRB groups, and a set ofPRB groups may be configured to UE via UE-specific signaling. The PRBgroup may consist of M PRBs which may be contiguous. M PRBs may bechosen such that the size is the same as one PRB based on the largestsubcarrier spacing that the NR carrier supports.

When a set of PRBs are used for UE-specific bandwidth, it may be basedon reference numerology (or, default numerology or base numerology) usedin synchronization. Or, it may be fixed in the specification. Or, it maybe indicated implicitly or explicitly via system information block (SIB)and/or master information block (MIB).

If carrier bonding is applied, the system bandwidth may be updated viaSIB and/or MIB. As mentioned above, center frequency and/or DC carriermay also be updated via SIB and/or MIB.

For the convenience, in the present invention, it is assumed that a NRcarrier consists of M PRBs, based on the reference numerology.

Hereinafter, various aspects of the UE system bandwidth in NR carrieraccording to embodiments of the present invention is described.

1. Subband Definitions

First, a minimum-subband (M-SB) according to an embodiment of thepresent invention is described. Assuming that the minimum bandwidth thata UE supports (at least enhanced mobile broadband (eMBB) UE or UE withrelatively high data rate) is K PRBs, and that a UE may support multipleof K PRBs, the M-SB may be formed as K PRBs or multiple of K PRBs. A UEmay support bandwidth between K*M PRBs to K*(M+1) PRBs, and a UE may beconfigured with K*M PRBs or (K+1)*M PRBs. In this case, some PRBs arenot used for UE scheduling. Different size of K may be supported by asingle NR carrier. For example, if there are three different UEbandwidths supported e.g. K1, K2, and K3, the system bandwidth may bedivided in to N1*K1 PRBs, N2*K2 PRBs, and N3*K3 PRBs. In other words,different sizes of subbands may be formed within the system bandwidth.

If the M-SB is defined in the system bandwidth, the transmission of suchas synchronization signals, physical broadcast channel (PBCH), etc., maybe performed within one of M-SB. The one M-SB may be called anchor M-SB.To keep synchronization signals, PBCH, etc., within the anchor M-SB, RBindexing may be started from the location of synchronization signals,PBCH, etc.

FIG. 7 shows an example of RB indexing according to an embodiment of thepresent invention. Referring to FIG. 7, RB indexing always starts fromthe center of anchor M-SB or center of synchronization signal (SS) blocktransmitted within anchor M-SB. If multiple SS blocks are present in theNR carrier, the starting index in which a common PRB indexing can startmay be indicated, or the offset between the center of M-SB or SS blockand the reference point for the common PRB indexing may be indicated. Assynchronization signal may present in edge of system bandwidth, theindexing should be sufficiently large (e.g. more than 2*maxRB).Referring to FIG. 7-(b).

Different from LTE, the resource indexing in NR may not be affected bythe system bandwidth (whether odd or even) to simplify the indexing.Furthermore, maxRB is the potential maximum RB size including guard bandto cover the largest system bandwidth that the NR supports. If maxRB istoo large, overall size of RB index may increase. Therefore, in order tominimize the indexing overhead, PBCH and/or SIB may indicate RB offsetwhich may be extracted from each RB index to reduce RB index value. Forexample, if maxRB is 10000, and system bandwidth is only 100 RBs, RBoffset of 9800 may be configured so that RB index can be fallen into therange of [0, 200]. Alternatively, maxRB may be determined from thesystem bandwidth indicated by PBCH/SIB, and maxRB may be defined as2*system bandwidth in RB.

Instead, if system bandwidth is not given, maxRB may be indicated wherethe UE may assume that system bandwidth of the NR carrier is smallerthan maxRB, and larger than the anchor M-SB. For example, when carrierbonding or carrier segment aggregation are dynamically utilized, thesystem bandwidth of the network which can change dynamically may not beindicated. Rather, any necessary information to form the RB grid may begiven. The numerology used in synchronization signal and/or PBCH, whichis called reference numerology (or, default numerology or basenumerology), may be different from the numerology mostly used in datascheduling or common signal scheduling. In terms of PRB indexing forPBCH, maxRB may be the same as bandwidth of PBCH. In other words, RBindexing for PBCH may be locally determined within PBCH bandwidth. Forother channels, center frequency and maxRB (either based on systembandwidth or defined value) may be used for RB grid formation.

The edge M-SB with smaller size than full M-SB may also be utilized fordata scheduling. If the system bandwidth is not known to UE, the use ofonly available PRBs may be handled by the network.

The definition of M-SB may be used only for common data, such as SIB,random access response (RAR), paging, etc.

If SIB is transmitted via PDCCH, the resource set for PDCCH carrying SIBmay also be restricted to the minimum bandwidth. The minimum bandwidthmay be defined as min (system bandwidth, UE minimum bandwidth). The UEminimum bandwidth may be defined in the specification, and may bedifferent per frequency range or band. The location and bandwidth ofPDCCH resource set within the system bandwidth may be indicated by PBCH.Also, necessary information for PDCCH resource set for SIB may beindicated by PBCH or additional PBCH. In terms of configuring commonsearch space (CSS) for PDCCH, the following options may be considered.

(1) Option 1: System bandwidth may be divided into a set of subbands,and each subband size is K PRBs. A set of PDCCH resource sets may bedefined/configured per each subband, and a UE may be configured tomonitor one of them. The same configuration may be applied for eachsubband. If this option is used, regardless of UE monitoring subband, aUE can search the same CSS. If this is used, configuration of CSS forPDCCH may include at least one of the followings.

Number of PRBs within a subband: The PRB may be started from the lowestfrequency or highest frequency. Or, additional offset may also beconfigured, or PRBs within a subband may also be explicitly indicated.

Number of OFDM symbols used for CSS

Blind decoding candidates per aggregation level (AL)

Transmission scheme and associated parameters for transmission scheme

The CSS for PDCCH may be configured/applied within a subband where a UEis configured to monitor. If a UE is configured with multiple subbands,the configuration may apply to the first subband or indicated subbandfor control monitoring. The benefit of this approach is that a UE is notrequired to change its SS configuration, even though the UE changes itsmonitoring subband. Also, within each subband, necessary synchronizationsignals and measurement reference signal (RS) may be transmitted.

(2) Option 2: Different search space may be configured per UE dependingon UE supported bandwidth. In this case, separate configuration may beconsidered depending on UE supported bandwidth.

FIG. 8 shows an example of configuration of different search space perUE according to an embodiment of the present invention. Referring toFIG. 8, UE1 monitors beam b1 and b2, and UE2 monitors beam b2 and b3.Further, bandwidth supported by UE1 is narrower than the systembandwidth, and bandwidth supported by UE2 is equal to the systembandwidth.

As synchronization signals may not be placed in the network carrier,depending on the synchronization signals, the relationship betweensubband and anchor subband may be different. In terms of placing anchorsubband, the following options may be considered.

(1) Option 1: Anchor subband may be placed only at one of the determinedsubband. The subband size may be determined based on the systembandwidth, and then, anchor subband should belong to one of subband. Forexample, when system bandwidth is 400 MHz, and the subband size is 100MHz, anchor subband should be one of four subbands. Within the anchorsubband, the location of initial synchronization signals may be flexibleand may be placed anywhere within the anchor subband. This may restrictthe possible location for initial synchronization signals. However, ifthere are different bandwidth supported by the network in the samefrequency band, it may also be desirable to have some alignment betweendifferent system bandwidth. For example, if one cell wants to operate in4*100 MHz and another cell wants to operate in 400 MHz, subband size of100 MHz may be beneficial to align different system bandwidth amongcells in the same frequency. However, again, this may restrict thepossible location of synchronization signals.

Subband formation may be defined per frequency range or per frequencyband. For example, current LTE band may be reframed or shared with NR,and in this case, subband can be 1 and the subband size may be same assystem bandwidth. In other words, subband may not be supported infrequency band equivalent to or overlapped with LTE frequency.Alternatively, if NR band is redefined which may span more than one LTEfrequency band, it is also possible that some UEs may not support thesystem bandwidth. In other words, the above condition may occur in suchcases as well. For that, fixed subband size, e.g. 20 MHz or 10 MHzdepending on UE minimum bandwidth requirement or typical UE RFbandwidth, may be decided even in frequency band overlapped with LTEfrequency bands.

If this option is used, the location of synchronization or SS block maybe limited by subband size. In other words, some synchronization rastermay not be used for synchronization signal mapping which may lead SSblock across subbands (i.e. not fully contained within a subband). Inother words, a UE may assume that some synchronization raster are notnecessary to be searched as there may be no synchronization signalmapping in such candidates, as it cannot be contained within onesubband.

(2) Option 2: Anchor subband may be formed based on initialsynchronization. Based on synchronization signals assuming that thecenter of SS block is the center of anchor subband, anchor subband maybe formed implicitly. The size of anchor subband may be defined in thespecification or configured by MIB. If this option is used, if thefrequency in which synchronization is transmitted are different amongneighbor cells, subband may not be aligned among neighbor cells.Furthermore, subcarrier and RB grid may not be aligned, either.

(3) Option 3: Anchor subband and other subband for UE-specific bandwidthmay be handled separately. In other words, subband formation may bebased on system bandwidth or specified in the specification perfrequency range or band as mentioned in Option 1, while synchronizationsignals may be transmitted without being tied with subband formation. Inother words, synchronization signals may be transmitted in anywhere, andthus, anchor subband may be formed overlapped partially or fully withsubband.

FIG. 9 shows an example of handling anchor subband and other subband forUE-specific bandwidth separately according to an embodiment of thepresent invention. Referring to FIG. 9, subband formation and anchorsubband are configured separately. Therefore, anchor subband whichcarries synchronization signal is overlapped with subband.

(4) Option 4: Subbands may be formed based on center frequency indicatedby the PBCH, and maximum system bandwidth may be defined per frequencyrange or per frequency band or may be indicated by MIB. In other words,subband size and maximum system bandwidth may be indicated by thenetwork, and actual system bandwidth may or may not be indicated. Suchvalues may be predefined in the specification which may vary dependingon frequency. When this option is used, a UE may not be able to accesssome subbands. In such case, the frequency region which the UE canaccess should be known to the UE via subband allocation or UE-specificbandwidth allocation or by common signaling. If the network adapts itsbandwidth dynamically for power saving depending on UEs, anchor subbandmay be included in the minimum system bandwidth. The bandwidth may beindicated as minimum system bandwidth. To allow dynamic bandwidthadaptation, it may also be possible to change dynamic reserved resourcewhich may be indicated by semi-static and/or dynamic signaling, such asgroup common PDCCH.

When subband formation is configured/defined, a set of subbands may beexplicitly indicated to a UE via group common signaling. Alternatively,a set of subbands may be implicitly indicated to a UE with start and endof frequency region with which a UE is configured. The frequency regionmay contain one or more subbands. In case of multiple subbands, a UE mayalso be indicated with additional information of subband within theconfigured frequency region.

Initial access subband according to an embodiment of the presentinvention may also be defined. When SS block size may be smaller thanthe subband size, CSS for SIB reading should be clarified. One approachis to configure CSS for SIB within the SS block so that a UE is notrequired to perform any frequency retuning. Another approach is toconfigure CSS for SIB by the MIB which may or may not require frequencyretuning. If subband is not formed based on SS block, at least for CSSfor SIB, it may be formed within the SS block or around SS block. Inother words, CSS for SIB may be indicated by PBCH.

At SIB, further information on CSS for other subband may be informed.Alternatively, anchor subband may always be formed part of subband. Tobe aligned with subband, the offset between subband center and SS blockcenter may be informed or based on system bandwidth, and accordingly,subband formation may be known to the UE. Alternatively, when CSS isconfigured, the PRB indexing of CSS may be configured based on thecenter of SS block. In other words, offset relative to SS block may beused for frequency location for CSS for SIB. Assuming maximum subbandsize or defined subband size, virtual RB indexing may be formed aroundSS block, and a set of PRBs may be configured for CSS. This implies thatPRB indexing is performed around SS block instead of center of thesystem bandwidth. When this approach is used, similar manner may be usedfor UL PRB indexing. Or, UL PRB indexing may be performed based on thecenter of uplink or based on a reference UL frequency. UL frequency maybe indicated for each UL carrier. As different UL center may beconfigured for different UEs, this assumes that center of UL carrier isindicated/informed via MIB/SIB.

When anchor subband is not part of subband or is overlapped withmultiple subbands, for PBCH, PRB indexing may follow PRB indexing withinSS block or minimum system bandwidth. Other PRB indexing for otherchannels may follow subband formation once subband formation is known tothe UE. In other words, a UE may assume SS block as a center for PRBindexing until it acquires information about system bandwidth's center.Or, UE may assume SS block center as PRB indexing's center regardless ofactual center. After that, PRB indexing may be based on subbandbandwidth or system bandwidth depending on the assumption or informationcarried on MIB. For example, if MIB carries system bandwidth, PRBindexing may be based on system bandwidth. And if MIB does not carrysystem bandwidth, PRB indexing may be based on subband bandwidth.

For initial access, anchor M-SB may be used. This is at least supportedfor unpaired spectrum. Alternatively, other region may be indicated e.g.via physical random access channel (PRACH) configuration. Based on PRACHconfiguration, a UE may switch UL frequency, and PRACH configuration mayalso include control subband (within an M-SB possibly) information whereRAR can be expected. M-SB of Msg3 may be dynamically or semi-staticallyconfigured by RAR or SIB (e.g. remaining system information (RMSI)). Asa default, the same M-SB for PRACH may be used for Msg3 transmission.For M-SB of Msg4, the same M-SB or same control subband for RAR may beused, or M-SB of Msg4 may be dynamically or semi-statically indicated byRAR or SIB. For data subband, unless otherwise configured, M-SB in whichcontrol subband is located may be used for DL data subband, and M-SB inwhich UL transmission is scheduled may be used for UL data subband fornon-UE-specific data transmission. The similar concept may be appliedfor single cell point-to-multipoint (SC-PTM) or any other multicasttransmission, sidelink, and broadcast mechanism.

UE-specific bandwidth for DL/UL according to an embodiment of thepresent invention is described. Control subband used for Msg4 may beused for UE-specific search space (USS), until it is reconfigured. InMsg3, necessary channel state information (CSI) feedback may bedelivered for supporting localized mapping. If any feedback is notsufficient, first distributed mapping may be used for search space forMsg4 and default USS. Default data subband for USS may be defined inM-SB in which Msg4 control subband is configured until it isreconfigured. This default data subband may be smaller than the UEcapable bandwidth. The UE may report its capability in terms ofbandwidth support via Msg3. Or, PRACH configuration may be configured sothat different bandwidth supporting UEs can select different PRACHresource and thus by detecting PRACH, the network can know the bandwidthcapability. When a UE is reconfigured with control region for USS,control subband for Msg4 may be used as a fallback purpose. In theconfiguration, search space split between new USS and default USS may beindicated, or a UE may need to search both until radio resource control(RRC) reconfiguration is completed where search space is split equallybetween two search space. Or, default search space may be kept forpossible fallback operation, PRACH operation, etc.

As long as it can be satisfied by UE capability in terms of RF/baseband,a UE may be configured with multiple data subband for DL and UL,respectively. More specifically, a transport block (TB) may be mappedfor each data subband, and one data subband may be overlapped withanother subband partially or fully.

FIG. 10 shows examples of different UE-specific bandwidth optionsaccording to an embodiment of the present invention. Referring to FIG.10, when multiple subbands are configured, it aggregation of subbandsmay be supported in different manners. Within a system bandwidth,depending on UE's data rate requirement, smaller bandwidth, which may becontiguous and non-contiguous, may be configured, and the frequencyregion(s) may be hopped to different region with or without frequencyretuning delay depending on RF bandwidth capability. One of the reasonto allow non-contiguous subband allocation is to enablefrequency-selective scheduling. FIG. 10-(a) shows a case ofintra-non-contiguous subband aggregation. FIG. 10-(b) shows a case ofintra-contiguous subband aggregation. FIG. 10-(c) shows a case ofoverlap subband aggregation. FIG. 10-(d) shows a case of subband overmultiple RFs. FIG. 10-(e) shows a case of control subband within UEbandwidth. FIG. 10-(e) shows a case of control subband within subband.

For convenience, the following subbands may be defined according to anembodiment of the present invention.

(1) Common data subband: There may be multiple common data subbandsdepending on common data type or purposes or radio network temporaryidentity (RNTI) or groups. For a given UE, there may be at most onecommon data subband for a given common data. Alternatively, the sameprocedure in UE data subband, which will be described below, may also beapplicable to common data subband. Once a UE is configured withUE-specific data subband, at least one or more of configured UE-specificdata subbands may also be used for common data subbands.

Common data subband may be defined separately for DL and UL. If thefrequency region is different and outside of UE RF capability (and thusrequire frequency retuning), the gap between DL/UL may also includefrequency retuning latency in unpaired spectrum. Frequency retuning mayalso be required if a UE has to switch center frequency. In that sense,if subbands are configured in different frequency regions which requiresswitching of center frequency, or need to adapt its center to optimizeRF filter, it may also require retuning latency.

(2) Common control subband: Common control subband corresponds to aregion in which control for common data is transmitted. Generally, thismay be a subset of common data subband. Or, common data subband andcommon control subband may be placed within an M-SB or anchor M-SB.

(3) UE data subband (or, just data subband): One subband may consist ofcontiguous or non-contiguous PRBs from a UE perspective. At least one ofthe followings may be defined per data subband.

Numerology used for data transmission: Single numerology is defined perdata subband.

Slot length, mini-slot length(s): TTI is defined per data subband.

RAT (e.g. NR, LTE) may be configured per UE data subband.

Maximum transport block size (TBS): Maximum TBS may be implicitlydetermined by the maximum number of RBs within a data subband, or may beexplicitly indicated.

Maximum one TB mapped to one data subband. The maximum one TB may be pereach layer if there are multiple layers. In this case, maximum number ofTBs with multiple layers may be still supported within one data subband.Initial transmission and retransmission may occur in the same datasubband or at least in the same data subband set. Data subband set maybe defined as a set of data subband with the same numerology, andpossibly different frequency domain resources and other configurations,such as control resource set configuration. A UE may be scheduled with aTB in at most one of data subband in one data subband set in a time.However, a UE may be scheduled with multiple TBs, and each TB may bemapped to one data subband in one data subband set, where multiple datasubband sets are configured and multiple data subbands are activated.

Data subband should be within a UE-specific bandwidth, and UE-specificbandwidth may change with time. In other words, a UE may be configuredwith multiple data subbands, and one data subband may be activated at atime. As mentioned above, at most one data subband is activated at agiven time from one data subband set. Data subband may be referred as abandwidth part (BWP).

(4) UE control subband (or, just control subband): One or more controlsubband may be configured. Each data subband may have one or morecontrol subbands, and the actual configuration may be separated and onlythe association may be indicated in data subband configuration. Controlsubband may be defined as follows.

Numerology used for control transmission: Single numerology is definedper control subband.

Monitoring interval: One configuration of monitoring interval is definedper control subband.

Resource element group (REG)/control channel element (CCE) index withina control subband: No cross REG/CCE indexing across different controlsubbands

REG/CCE resource mapping manner: Localized or distributed may beconfigured.

2. Control Subband and Data Subband Mapping

The mapping between control subband to data subband may be 1-1 or n-1 orn-m or 1-m. Details are as follows.

(1) One control subband may schedule data to only one data subband.Accordingly, there is no need to indicate data subband in the resourceallocation.

(2) Multiple control subbands may schedule data to one data subband: asit is still exclusive, there is no need to indicate data subband inresource allocation.

(3) One control subband may schedule data to multiple data subbands, andone data subband may be scheduled by multiple control subbands. In thiscase, indication of data subband is necessary. Data subband may beindicated in resource allocation or indicated separately. Alternatively,if one control subband schedules multiple data subbands, control subbandor search space may be separated among data subbands. One approach is todivide candidates among multiple subbands. Another approach is to divideCCEs among multiple subbands. Particularly, this may be useful if anchoror primary subband is configured to a UE, and additional secondarysubband(s) may be activated/deactivated dynamically. More details willbe described below (5. Dynamic bandwidth sharing with SB-aggregation).

Further, when one control subband schedules data to multiple datasubbands, subband index also needs to be identified in controlinformation. First, one control subband may schedule one data subbandfrom the same data subband set at a given time. As mentioned above,change of bandwidth without changing numerology may be realized byadding time-domain aspects on data subband or configuring multiple datasubbands. In this case, multiple data subbands are formed as one datasubband set. In this case, data subband change may be explicitlyindicated or implicitly indicated depending on the data subbandswitching among data subbands belonging to the same data subband set.Second, one control subband may schedule one or multiple data subbandsfrom multiple data subband sets at a given time. In this case,regardless of change of data subband within a data subband set,indicating data subband set is necessary. Both may be combined, andindication in DCI or resource allocation may indicate a data subbandindex. Data subband index may be uniquely configured for each data bandregardless of data subband set. This may be particularly beneficial if aUE can be activated with multiple data subbands (or BWPs) and alsosupport bandwidth adaptation across slots via scheduling DCI.

Further, it may be considerable to allow any configuration by thenetwork. In this case, for each control subband, a set of data subbandswhich control subband may schedule may be indicated. If there is onlyone data subband, in resource allocation or additional field on datasubband index may be omitted. If there are more than one data subbands,some indication on subband may be necessary. However, this may leadvariable DCI size depending on the configured data subband. To addressthis, alternative approach is to assume that any control subband canschedule any data subband, and thus, the number of configured datasubband to the UE is assumed for all resource allocation. For thecontrol subband which schedules only one data subband, this field may bereserved. Alternatively, the size of data subband index fields may beconfigured for each control region. The bit size to indicate datasubband index may be variable depending on the configured data subbandto the UE (or for common data if configured). Bit size may also be zeroif only one data subband is configured.

When multiple data subbands and control subbands are configured,UE-specific bandwidth may be defined as superset of data/controlsubbands in contiguous PRBs, or UE-specific bandwidth may be configuredseparately. If superset is used, the lowest PRB and the highest PRB inthe configuration may define the UE-specific system bandwidth.

3. UE Capability

Depending on UE RF capability, a UE may be configured with more than onecontiguous or non-contiguous UE-specific bandwidth (or UE-specificcarrier). For example, a UE may support the following cases.

A UE may support contiguous intra-band carrier aggregation (CA) and/ornon-contiguous intra-band CA with X1 . . . Xk (in case K carriers)system bandwidth. That is, a UE may support intra-band CA with less thank RF components. this case may be more necessary if the system bandwidthin NR is defined smaller than a UE typical RF capability

A UE may support maximum RF bandwidth Xm≥max {X1 . . . Xk} in the band(at least in one RF component). That is, a UE may support intra-band CAwith single RF. In this case, RF capability may include sum of supportedbandwidth.

A UE may support k different RF components.

A UE may not be configured with intra-band CA with the capability of oneRF component. For example, even if a UE supports 30 MHz, the network maynot configure 10+20 MHz carriers unless the UE can support also 10+20MHz carrier aggregation. In this case, the network may allocate 30 MHzcarrier, and then may allocate 10+20 MHz data subbands aggregation. Thisimplies that a carrier may have smaller system bandwidth than the UEtypical/minimum RF capability, but the network cannot allocate a carriersmaller than the UE typical/minimum RF capability bandwidth carrier forintra-band contiguous CA. More generally, in only a few sets of UE RFcapabilities, system bandwidth can be larger than combinations of UE RFcapabilities (e.g. twice of maximum UE RF capability, sum of capabilityvalue 1+capability value 2).

This implies that a UE has separate RF to support intra-band contiguousor non-contiguous CA. In this case, a UE needs to be configured with acarrier per RF, and then may be configured control/data subbands withinthe carrier. UE-specific carrier may be different from the carrier ofthe network. Also, UE-specific carrier may not carry any synchronizationsignals, and may not include any anchor M-SB. The UE-specific carriermay be called UE-specific supported bandwidth. Control/data subbands maybe configured across UE-specific supported bandwidth, and the guard bandbetween UE-specific supported bandwidth may be indicated to the network,and/or may be avoided in scheduling or by rate matching/puncturing.Another approach is to separate control/data subbands configuration perUE-specific supported bandwidth. This may be viewed as that theUE-specific supported bandwidth is treated as the carrier from a UEperspective.

FIG. 11 shows an example of UE-specific supported bandwidth according toan embodiment of the present invention. Referring to FIG. 11,control/data subbands are separated per UE-specific supported bandwidth.More specifically, three data subbands are defined and one data subband(D-SB2) is across UE-RF BW or UE-specific supported bandwidths, and onecontrol region is defined across both UE-specific supported bandwidth.

To determine UE capability, the network can use RF capability andbaseband capability, and at least one of the followings may beconsidered.

A UE may indicate maximum supported RF capability per band separatelyfrom baseband capability. This may allow frequency region switchingwithout retuning latency. The maximum supported RF capability may bepredefined. Also, if UE RF requires resynchronization outside of Nbandwidth, a UE may not be configured with any subband outside of Nbandwidth (centered at the anchor M-SB) or additional synchronizationsignals/tracking RS may be transmitted in different subband.

A UE may indicate maximum support baseband capability per band

A UE may indicate intra-contiguous/non-contiguous CA capability perband. This capability may be used for subband aggregation within acarrier if the network supports larger bandwidth carrier than a UE cansupport with one RF components.

If a UE supports inter-band CA, the supportable baseband capability perband may be reduced. In other words, if a UE can aggregate basebandcapability for different carriers to one carrier, the UE may report theaggregated baseband capability per baseband. For inter/intra-band CA,the total baseband capability may be indicated which may be divided toaggregated carriers by the network. If a UE cannot support flexiblepartitioning of capabilities between carriers, the UE may also indicatebaseband capability per band for each band combination. For each bandcombination, supported RF bandwidth on each band may also be indicated.

NR UEs may flexibly share baseband capabilities between carriers(possibly except for fast Fourier transform (FFT)), mainly oncontrol/data decoding capabilities. Thus, the total basebandcapabilities may be indicated per band and band combinations which areshared, and may be partitioned by the network. If a UE cannot supportflexible baseband capability sharing, the UE may indicate individualbaseband capability per band in a band combination.

4. Resource Allocation

First, data subband configuration according to an embodiment of thepresent invention is described. Though frequency selective schedulingmay be beneficial, a large TB may be scheduled across larger bandwidthto minimize control overhead. One of the mechanism to address this issueis to define subband in a nested manner. For example, two data subbandsare formed and another subband which covers both data subbands may beformed.

As long as the scheduled TBS over the configured data subbands is lessthan the UE baseband capability, a UE may attempt to decode all data.Also, the size of data subband may be configured as 2k*M PRBs, based onthe minimum size M.

Second, resource allocation aspects within a data subband according toan embodiment of the present invention is described. A data subband mayconsist of contiguous or non-contiguous PRBs. The index of PRBs withinsystem bandwidth (regardless of knowing the system bandwidth or not) maybe known to the UE for the given data subband. For determining resourceallocation bit size, the following approaches may be considered.

(1) The number of PRBs possible within a UE supported bandwidth may beused for resource allocation. If a UE can support wide bandwidth bymultiple RF, regardless of RF activation status, the total bandwidthsupported by the UE may be used. Otherwise, if it is smaller than systembandwidth, system bandwidth may be used.

(2) The maximum number of PRBs configured to a data subband for a givenUE may be used for resource allocation for any DL control information.In case of non-contiguous PRBs, only configured PRBs may be counted. IfRBGs are used for resource allocation, the maximum number of RBGsconfigured to a data subband for a given UE may be used for resourceallocation. The motivation is to align the size of resource allocationfield for all configured subbands.

(3) Each control region may be configured with the number of PRBs usedin resource allocation field. This should be larger than the allocatedPRB s, but it may be up to the network to determine the size.

(4) The same resource allocation size maybe kept by adapting resourceblock group (RBG) size in resource allocation. If data subband size is afunction of M*2k, to keep the same size of resource allocationregardless of data subband size, RBG size may also be increased by 2k.If the data subband size is M, RBG size may be assumed as P. Then, itmay increase by P*2k if M*2k is configured to the data subband size.

(5) In all cases, unused bits may be reserved, or may be used for someother purposes.

In terms of RB indexing, two approaches may be considered. Within eachdata subband, RB indexing may be done individually. Or, RB indexing mayfollow RB indexing of the system.

FIG. 12 shows an example of individual RB indexing according to anembodiment of the present invention. However, individual RB indexing maylead ambiguity in terms of RB indexing between different UEs. Further,this approach may also confuse any common data mapping, and may degradeRS sequence performance, etc.

In this sense, logical PRB index, which may be mapped to 0, 1 . . . N(N+1 is the number of PRBs in a data subband) per each data subband, maybe used. Logical PRB to physical PRB mapping may be continuously done ifcontiguous PRB is assigned for a data subband. For non-contiguous PRBswithin a subband, a logical PRB index may be constructed as 1 . . . N(in ascending order) for each allocated PRB for resource allocationpurpose. If virtual PRB is applied, the index may be used after physicalPRB to virtual PRB mapping is applied. However, in terms of datascrambling, RS mapping, etc., physical PRB index should be used insteadof logical index. Logical PRB index may be used only for resourceallocation purpose.

Based on the logical PRB index, the following resource allocationmechanisms may be applied.

(1) RBG based resource allocation: RBG size may be defined by the sizeof data subband if it is contiguous. As mentioned before, RBG size maybe defined proportional to the size of data subband. If it isnon-contiguous, RBG size may be fixed or configured by the network. Thismay be applied to contiguous case. The RBG size configuration mayindicate one set out of two sets (one set consists of RBGs sizes perbandwidth ranges). Based on the configuration, RBG size may bedetermined per each data subband.

(2) Compact resource allocation: As mentioned above, the field size maybe determined by maximum of the configured subbands or maximumconfigured by the network or configured subband size.

(3) Contiguous resource allocation: Demodulation RS (DM-RS PRB) bundlingsize may be configured per UE or per subband or per control subband, ifphysical resources are non-contiguous within a PRB bundling based onlogical PRB index. A UE may not assume the same precoding betweennon-contiguous PRBs. In other words, PRB bundling may not be appliedacross physically non-contiguous PRBs. For example, if logical PRB index3, 4, 5 indicates PRB index 20, 21, 44, which are grouped as bundledPRBs for precoding, bundling may be applied only for PRB index 20, and21. Alternative approach is to apply PRB bundling based on the bundlesize on PRB rather than logical RB.

(4) Hopping: If hopping is enabled, hopping may be applied only within adata subband. Alternatively, if retuning latency is considered, hoppingmay also be applied within a carrier. More specifically, hoppingbandwidth may be configured per each control subband (UE-specificallyfor USS, cell-specifically for CSS) or cell-specifically.

(5) Resource allocation type: If data subband is formed to utilizefrequency selective scheduling, it may be generally desirable toschedule data rather contiguously at least within a RBG. In this case,it may be configured with resource allocation based on contiguousmapping (i.e. compact resource allocation). If a subband is formedacross larger bandwidth, distributed scheduling may be useful. In thatcase, bitmap on RBGs may be used. Further, resource allocation type persubband may be configured regardless of transmission scheme used or DCIformat used. However, if different resource allocation size is used withallocation type (e.g. resource allocation type 0 vs allocation type 2),it may lead different allocation size on a subband. If any subband isscheduled by a control subband, this may lead possibly different DCIsize. One approach to address this is to use the same size resourceallocation type scheduled by a control subband by restricting set ofdata subbands. Alternatively, resource allocation type may be configuredper control subband, and it may be applied for subband scheduled by thecontrol subband.

5. Dynamic Bandwidth Sharing with SB-Aggregation

For battery saving or efficient operation depending on the necessarydata bandwidth, bandwidth for control/data reception/transmission may beadapted semi-statically or dynamically. One easy approach to utilizedynamic bandwidth sharing is to allocate anchor data subband or primarydata subband (PSB). The anchor data subband or PSB may not be changedregardless of bandwidth adaptation (or, may change semistatically).Further, supplemental or secondary data subband (SSB) may be dynamicallyaggregated or not aggregated. Subband size may also be changeddynamically. If SSB is allocated, which can be indicated by DCI, a TBmay be mapped to anchor subband or SSB or both. In other words, a UE maybe configured with more than one data subbands and one data subband sizemay be small and the other data subband size may be large. Switchingbetween two may be done by DCI, such as indication of data subband inDCI. In terms of configuration of multiple data subbands, nestedstructure among configured data subbands may be considered.

As a UE may require time to adapt its bandwidth, another approach is toapply same-subframe scheduling for anchor subband, and cross-subframescheduling for SSB. This may be applied only for the case that SSB isactivated/added. More specifically, a UE bandwidth may be allocated forfixed subbands and variable subbands. Fixed subbands may not be changed,whereas variable subbands may be changed depending on data rate orcases. A separate TB may be scheduled in fixed and variable subbands,and scheduling on variable subbands (or SSB) may be activateddynamically via scheduling. In this case, to allow a UE to adapt itsbandwidth, additional delay may be added between control and data (whichmay be done via cross-slot/subframe scheduling or adding a gap betweencontrol and data). If gap is not explicitly given, a UE may skipdecoding of the first few OFDM symbols carried in variable subband(s).In this case, anchor subband may be treated as primary cell (PCell) inLTE CA, and SSB may be treated as secondary cell (SCell) in LTE CA.Similar mechanism used for SCell addition/deactivation may be used forSSB activation/deactivation. However, this SSB may not carry additionalsynchronization signals, and synchronization may be done in anchorsubband.

As mentioned above, for this case, control subband may be configuredwithin only anchor subband (or, PSB). In this case, the control subbandmay carry control information of all subbands. Or, control subband maybe configured across PSB/SSB or per each subband.

This is somewhat similar to CA case with self-carrier and cross-carrierscheduling.

Accordingly, similar techniques used in CA may be applicable. However,if only one control subband within anchor subband is configured,depending on the activated SSB(s), different behavior on control channelmonitoring may be considered as follows.

(1) Control subband size may be expanded (i.e. the number of CCEs may beincreased) with more activated subbands. One approach is to expand intime domain to increase number of CCEs which may be done semi-staticallyor dynamically. If one control subband schedules one TB across multiplesubbands, resource allocation fields in DCI may be increasedaccordingly, which may require more resources to transmit controlchannels.

Also, the increased control subband may be divided between multiplesubbands. For example, hashing function in each subband may be used todetermine the starting CCE to search (either per AL or same across AL).In other words, CCEs or search space may be divided between multipledata subbands. In this case, separate field on subband index may not benecessary as it may be differentiated by the candidate. If candidatesfor different data subbands collide, smaller subband index may havehigher priority. In this case, the number of blind decoding may be(semi-) linearly increased with number of activated data subbands.Common data may be scheduled only via PSB, and thus, additional blinddecoding on common data may not be used (similar to current CA). Thismay not be applied to all common data, but only to fallback and transmitpower command (TPC) related common data.

(2) Control subband size may be kept as same with the increased numberof blind decoding. As mentioned above, blind decoding may be increasedwith the number of activated subbands. In this case, as similar asabove, search space may be separated among activated subbands (i.e. theabove mechanisms may be applied in this case).

(3) Control subband size may be kept and the number of blind decodingmay be kept as same. In this case, as mentioned above, subband index maybe carried in DCI, or search space may be divided among multiple datasubbands. If the number of blind decoding is relatively small, it isgenerally desirable to carry subband index in DCI. This option is tominimize UE complexity in term of blind decoding.

If one control subband schedules multiple data subbands, rate matchingon control region may be applied only within one data subband. If a UEdetects two DCIs schedule PSB and SSB, a UE may still assume data ratematching on control subband scheduling data. In other words, onlyresources used for the corresponding scheduling control may be assumedfor data rate matching (in addition to semi-statically configuredresources for rate matching). Alternatively, in each scheduling DCI, thenumber of scheduled PDSCHs across multiple subbands may be indicated,which may also be used for data rate matching purpose.

FIG. 13 shows examples of dynamic bandwidth adaptation via data subbandaggregation according to an embodiment of the present invention. Datasubband mentioned in the present invention may be renamed asdata-configured subband (D-CS). Referring to FIG. 13-(a), CA-likeoperation is utilized. Depending on traffic or power consumptionrequirements, a UE may be configured with one or multiple data subbands.The drawback of this approach is potential control overhead toseparately schedule different TB per data subbands. As CA-like operationmay be utilized, the impact of dynamic bandwidth adaptation may besimplified. For example, if a UE is configured with bandwidth-A for lowtraffic rate, and bandwidth-B for high traffic rate, two data subbandsmay be configured to a UE. First data subband may cover bandwidth-A, andthe other data subband may cover bandwidth-B—bandwidth-A. In this case,bandwidth-B may be achieved via data subband aggregation.

Further, to minimize control overhead, another approach is to configuretwo data subband, and first data subband may cover bandwidth-A and theother data subband may cover bandwidth-B. In this case, two data subbandmay partially overlap. FIG. 13-(b) shows a case that two data subbandsare partially overlapped and FIG. 13-(c) shows a case that two datasubband are not overlapped. Depending on scheduling, a UE may determinewhich data subband is activated, and dynamically adapt its bandwidth.

FIG. 14 shows examples of bandwidth adaptation via data subbandaggregation with multiple RF according to an embodiment of the presentinvention. If a UE supports wideband with multiple RFs in a NR carrier,one or more D-SBs may be turned on/off to adapt the overall databandwidth.

6. Subband Aggregation Activation

For subband aggregation activation, similar approach used in CA may beused (i.e. via media access control (MAC) control element (CE)). Ifsubband size is also dynamically changed, this activation message mayalso include the size of activated subband. Different from CA, subbandaggregation may not require radio resource management (RRM) measurementon the aggregated subband. However, it may be necessary to obtain CSIfeedbacks on candidate subbands where one or more subbands (partially orfully) can be activated. In this sense, aperiodic wide-subband requestmay be triggered for the configured subbands. In other words, a UE maybe configured with a list of potential subbands and a UE may be requiredto perform aperiodic CSI measurement which may be based on one-shot orbased on aggregated measurements. Aperiodic CSI request may be requestedon one or more configured subbands, and for the deactivated subbands,only wideband CSI measurement within the subband (i.e. wideband channelquality indictor (CQI)/precoding matrix indicator (PMI) over the entiresubband) may be reported. If a UE RF does not support CSI measurementwithout RF retuning/adaptation, additional and/or shared (withinter-frequency) measurement gap may be required. Before activating asubband, wideband CSI report may be expected generally, and a UE mayhave to adapt its RF to perform CSI measurement. Thus, generally, theprocessing time between aperiodic CSI trigger to report on deactivatedsubbands may be longer than aperiodic CSI processing time on activatedsubbands, unless deactivated subbands' CSI are also periodicallymeasured.

7. Reconfiguration of Data Subband

When a UE is configured with additional data subband within a UE RFbandwidth, depending on subband configuration, it may be sometimesnecessary to retune its center frequency (receiver center). If frequencyretuning is needed, sufficient gap may be needed. For one approach toallow this gap, time between the end of PDSCH which carriesreconfiguration message and the start of next may be used for retuninggap. If a UE is scheduled with any UL in that gap, a UE may drop any ULfor retuning. To minimize the gap, it is generally desirable to keep thecenter frequency unchanged if data subband is changed dynamically or aUE is allowed to change its RF bandwidth for datareception/transmission. In order to mandate this indirectly, resourceblocks for resource allocation may always be configured in a nestedmanner based on the first semi-statically configured data subband. Forexample, a UE may be dynamically configured with data subband sizebetween [M, 2*M, 4*M, 8*M . . . ] PRBs, where M is the minimum size ofdata subband. To minimize control subband change, control subband may beformed within M PRBs. To keep the resource allocation field intactregardless of data subband bandwidth adaptation, RBG size may beincreased with the increased data subband size.

FIG. 15 shows an example of resource allocation in a nested manneraccording to an embodiment of the present invention. Referring to FIG.15, a UE is dynamically configured with data subband size between [M,2*M, 4*M] PRBs, where M is the minimum size of data subband. This may bepreconfigured as possible patterns, and one of patterns may bedynamically or semi-statically indicated. In case of dynamic indication,which pattern is used or which data subband bandwidth size is used mayneed to be dynamically indicated. If a UE is dynamically configuredbetween BW-A (M PRBs), and BW-B (4*M PRBs), one bit may be added to DCIto indicate which size is being currently used for data scheduling. If aUE does not need any retuning, instantaneous RF spanning may be assumed.Otherwise, some gap for retuning latency may be assumed.

The size of data subband may be semi-statically changed as well. Withsemi-static change, fallback messages may be scheduled based on minimumdata subband bandwidth size for resource allocation, or based on defaultdata subband bandwidth size configured or indicated by the network. Inother words, during reconfiguration, or DCI scheduled on fallback,search space may assume different data bandwidth for resourceallocation. For example, minimum size of BW-A (M PRBs) may be used forfallback signaling. When semi-static change of data subband size occurs,necessary reconfiguration of semi-static resources may also benecessary, particularly for resources configured with offset value basedon the bandwidth (e.g. PUCCH resource offset). Also, for example,bandwidth of wideband CSI-RS may need to be adapted. The bandwidth maybe determined by DCI if dynamic change is adopted, and semi-staticadaption may be achieved when semi-static reconfiguration is applied.Once reconfiguration is done dynamically or semi-statically, RB indexing(if RB indexing starts from the lowest frequency) may be changed. Inthat sense, during fallback operation or reconfiguration, particularlywhen data subband size is changed, it is not desirable to schedulefallback message (e.g. RRC configuration message) with user data.

8. CA Handling

If multiple carriers are present, from a UE perspective, one datasubband may be configured across multiple carriers or within onecarrier. Furthermore, more than one data subband may be configured witha UE-specific bandwidth. If multiple data subband is configured in UL,as different TTI may be configured or different RAT is configured, themapping of DL data subband and UL data subband may be necessary.Accordingly, the following options may be considered.

(1) Any DL data subband may be mapped to a UL data subband. All uplinkcontrol information (UCI) corresponding to any DL data subband may betransmitted in any UL data subband.

(2) UL data subband may be divided into a few groups. All UCIcorresponding to any DL data subband may be piggybacked to PUSCH of anyUL data subband. In case of PUCCH transmission, DL data subband may begrouped as well and each group between DL data subband and UL datasubband may be mapped.

(3) UL data subband and DL data subband may be grouped and a DL datasubband group may be mapped to only one UL data subband group. UCIpiggyback, PUCCH transmission, CSI trigger, etc., may be handled withineach UL data subband group.

9. RRM Handling

When the system bandwidth is wider than the UE supported bandwidth, thefollowing two approaches may be considered for RRM.

(1) Subband approach: A network configures/operates one widebandcarrier, and a UE may monitor one or multiple subband(s).

(2) Carrier approach: A network configures multiple narrowband carriers,and a UE may be configured with one or multiple carriers, likeintra-band CA.

When the subband approach is considered, the following aspects should beclarified in each subband where a UE is configured to monitor for DL.

Whether CSS is configured separately per each subband

Whether synchronization signal is transmitted per each subband

Whether measurement RS is transmitted per each subband

Whether tracking RS is transmitted separately per each subband

Whether PBCH and/or SIB is transmitted separately per each subband

Whether RACH procedure can occur within each subband

Whether resource allocation is restricted within a subband

When the subband approach is considered, three options may be furtherconsidered for SS block transmission as follows.

(1) Each subband may carry SS block and any SS block may be accessed bystand-alone UEs.

(2) Only anchor subband may carry SS block. There may be one anchorsubband across multiple carriers, i.e. one carrier may not carry SSblock.

(3) Whether each data subband may carry SS block may be based onconfiguration. From a UE time/frequency synchronization perspective, aUE may assume that the SS block in initial access may be used for thereference, until it is handed over to another SS block.

If option (1) is used, SS block transmission overhead may be added,particularly if small interval is used for synchronization signalperiodicity. Also, as different UEs can access different SS blocks, someinformation on PBCH and/or SIB may need to be different per eachsubband. For example, if the offset of center frequency of the systembandwidth and center frequency of the SS block is indicated, the valuemay be different per each subband. While option (1) adds some burden, itmay simplify UE measurement, particularly for neighbor cell measurement.

If option (2) is used, to support RRM measurement for UEs in differentsubband from the anchor subband, it may be necessary to transmitadditional signals for cell detection and measurements. However,compared to option (1), at least different frequency of SS blocktransmission or additional transmission may be considered (e.g. sparsertransmission). If there are UEs in a subband which are not capable ofmonitoring CSS configured in different subband or anchor subband, CSSmay be additionally configured if the subband approach is used.

It is described that thee options mentioned above are applied to thesubband approach. However, three options may also be applied to thecarrier approach. Even with carrier approach, only anchor carrier maycarry the SS block for initial access, and other carrier may transmitadditional signaling similar to the subband approach.

When the subband approach is used, it may efficiently handle UEssupporting larger bandwidth than the bandwidth of a subband. For suchUEs, multiple subbands may be configured and one TB may be mapped to oneTB.

When a UE is equipped with multiple RFs for supporting wider bandwidth,both subband approach and carrier approach may be considered. In LTE,the case has been supported by intra-band CA. As discussed above, eachsubband may carry necessary synchronization and RRM RS, and possiblyPBCH/SIB transmissions. In that sense, either by subband or carrierapproach, similar overhead may be expected by supporting the followings.

From the network operation perspective of a wideband, the network maydefine an anchor subband/carrier where SS block for initial access istransmitted. In other subbands, additional signals may be transmittedfor measurements if there are UEs requiring transmission.

From a UE perspective, regardless of whether the network utilizessubband approach or carrier approach, the UE may be configured with oneor multiple of data subbands. This may be efficient at least if thenetwork manages multiple carriers with the anchor carrier andsupplemental carrier to minimize initial access overhead or the networkoperates different numerologies in different frequencies.

FIG. 16 shows an example of different handling options for widebandspectrum with narrowband UE RFs according to an embodiment of thepresent invention. In FIG. 16, for the convenience, a component carrierdefined by the network (or from the network perspective) is calledN-carrier. Also, a component carrier defined by the UE (or from the UEperspective) is called U-carrier. FIG. 16-(a) shows mapping betweenN-carrier and U-carrier for multiple RF over single wideband. FIG.16-(b) shows mapping between N-carrier and U-carrier for multiple RFover multiple narrowband.

10. Single Data Subband Mapping with Multiple RF

As discussed above, one data subband may be configured to span a singleor multiple UE RF bandwidth. As the UE is equipped with multiple RF,some issues related to phase continuity and/or power amplifier may needto be clarified. If a UE can support reception of data with phasecontinuity regardless of actual RF, the UE may indicate its capability.In terms of capability, whether a UE can support wideband via multipleRFs or not may be indicated. Baseband capability may not support thisoperation. In this case, a UE may need to inform that each RF supports acertain bandwidth, multiple RFs can support multiple of narrowbands, andeach narrowband is supported by one RF. This is similar to CA from a UEperspective. For UL, some considerations needs to be addressed.

(1) If a UE is configured with discrete Fourier transform

(DFT)-spread-OFDM (DFT-s-OFDM), as the UE may need to perform spreadingseparately per RF, whether a UE can support multiple DFT-s-OFDMsimultaneously or not may be indicated. In case of separate RF, separatehandling on potential DC may be necessary and a UE may indicate a set ofpotential DCs for each RF. Or, a UE may indicate potential multiple DCsconsidering multiple RFs. If a UE supports simultaneous ULtransmissions, the network may schedule one or multiple TB s acrossmultiple UL resource regions which may be handled via one or multipleRFs. The set of RBs transmitted via one RF may need to be informed tothe network or to other UEs (e.g. in sidelink operation). This may benecessary particularly when channel estimation or PRB bundling isassumed and PRB bundling would not cross the RF boundary.

(2) If a UE is equipped with separate power amplifier in two RF, thepower split between two RFs may be necessary which may be independentlyconfigured/indicated by the network. If the network schedules one TBover multiple RF transmissions, the following approaches may beconsidered.

The parameters of power control may be applied commonly across the RFs,the power assigned in each power amplifier or RF may be determined bythe common power parameters with the allocated RB within the RFbandwidth or RBs covered by the RF. If power limited, power scaling ordropping may occur based on priority, such as UCI type.

The parameters of power control may be configured separately and thepower assigned in each power amplifier or RF may be determined by theindependently configured parameters with the allocated RB within the RFbandwidth. This approach makes more sense when separate UL transmissionis configured by the network and power control is performedindependently per RF. To support this, one DCI or one UL grant mayindicate different TB across different PRBs. Separate configuration onDM-RS may also be considered. If separate power control is used,separate TPC command may also be necessary.

(3) Control channel monitoring

For better channel estimation, one control resource set may be confinedwithin one RF bandwidth. Further, multiple control resource sets may beconfigured for multiple RFs. Even if it allows a control resource set tobe mapped over multiple RFs, at least one control resource set orcontrol resource set for common search space may be confined within theprimary RF bandwidth. This is to minimize ambiguity of controlmonitoring subframe regardless of activation/deactivation of RFs otherthan the primary RF. If a control resource set spans multiple RFs,search space may be constructed so that at least partial candidates canbe located within the primary RF bandwidth. This may be done e.g. by notdistributing adjacent (logically) CCEs across different RFs. In otherwords, when CCEs are distributed, it may be distributed within one RFbandwidth. As common search space or group-common search space is sharedby multiple UEs which may have different RF bandwidth supported, it mayneed to be clarified how each UE can access or how search space isconfigured. The following approaches may be considered.

Group common search space may be configured within the smallest RF amongUEs which share the same search space. If USS and C/GSS shares the samecontrol resource set, only partial bandwidth may be shared between USSand C/GSS. To support this, control resource set may be virtuallydivided into fixed and variable resource set, and CCEs may be mappedindependently between fixed and variable resource set, and possiblydifferent transmission scheme may also be considered between twodifferent resource regions. Alternatively, CCEs may be mapped in a waythat only the first M CCEs are mapped within the smallest RF bandwidthregion where a set of candidates are restricted for C/GSS, whereas USScan be mapped over the entire control resource set.

Group common search space may be configured within the nominal RF whichis defined in the specification or by configuration, and a UE supportingless bandwidth than the nominal RF may not be able to access some searchspace candidates or have restriction.

Separate group common search space may be configured per differentbandwidth UEs. The UEs sharing the same search space may have the sameRF bandwidth capability at least from the control monitoringperspective.

(4) Data mapping

One TB may be mapped over multiple RF bandwidth. However, one DCI, whichcan schedule two different TBs or multiple TBs, may be transmitted overmultiple RFs. In other words, one DCI may schedule separate resourceallocation for different bandwidth with different RF. Alternatively,resource allocation may be done based on the single RF bandwidth and thesame resource allocation may also be applied to different RF. Forexample, if resource allocation schedules PRB 1 to 15 for one RF, it maybe assumed that the PRB within the RF is allocated to the UE. If it isconfigured to apply the same resource allocation to different RFs, itmay be assumed that PRB 1 to 15 for each RF is also allocated to the UE.To support this, each DCI may carry N bits, where N is the number of RFsexcept for the primary RF which are activated. Further, whether the sameresource allocation is applied or not may be indicated via the bitmap.

Alternatively, resource allocation may be done based on the aggregatedbandwidth by the multiple RFs. In this case, resource allocation bycommon search space or group common search space may be restrictedwithin the bandwidth covered by primary RF. The similar restriction mayalso be applied to the case of bandwidth adaptation even with single RF.In this case, CSS may be restricted to the minimum bandwidth, andresource allocation by CSS may be restricted to the configured bandwidthor minimum bandwidth to avoid ambiguity. In other words, the bandwidthin each search space may be different. Further, different bandwidth pereach search space or control resource set may be configured as well. Tominimize the overhead, compact resource allocation may be used forcontiguous resource allocation, or different RBG may be considereddepending on the configured RFs or the aggregated bandwidth. In otherwords, even though the system bandwidth is same to all UEs, depending onthe supported bandwidth by each UE, RBG size may be different and RBGsizes among different bandwidth may also be multiple values of eachother (e.g. RBG size is 2 PRBs for 5 MHz, 4 PRBs for 10 MHz, 8 PRBs for20 MHz, and so on).

(5) PUCCH Transmission:

If distributed mapping for PUCCH is supported, PUCCH transmission may beconfined within one RF regardless of the aggregated bandwidth supportedby the UE. This is mainly useful if DFT-s-OFDM is used. However, evenwith OFDM, this may be beneficial for power control, etc. In otherwords, PUCCH resource may be configured differently based on RFinformation from each UE. If PUCCH is transmitted only via primary RF,the PUCCH resource configuration may be confined within primary RFbandwidth. Alternatively, PUCCH resource mapping may occur acrossmultiple RFs, in which long PUCCH with low peak-to-average power ratio(PAPR) may not be easily supported or simultaneous transmissioncapability may be necessary. Further, a UE may support DFT-s-OFDM andOFDM simultaneously via different RF which may be indicated to thenetwork. This may be efficient if simultaneous UL transmission todifferent gNB or transmission/reception points (TRPs) are supported andone may require coverage and the other may require efficientmultiplexing. If the UE does not support simultaneous transmission oftwo waveforms, one waveform may be configured semi-statically ordynamically. Long PUCCH and short PUCCH may also be transmittedsimultaneously regardless of waveform used. Cross-UCI piggyback amongdifferent RF may also be supported.

(6) PRACH Transmission

Multiple RF reception may be enabled by UE-specific higher layersignaling. In other words, Multiple RF reception may be activated when aUE is in RRC connected state. If multiple RF is enabled even before RRCconnected state, a UE should support seamless/transparenttransmission/reception. In this case, PRACH resource may be confinedwithin a UE minimum bandwidth so that all UEs can transmit PRACH withsingle RF. Or, different PRACH resources may be configured withdifferent PRACH bandwidth.

(7) CQI Transmission

Subband partitioning may be constructed based on the aggregated widebandbandwidth. Single wideband CQI may be indicated over the wideband.However, partial wideband CQI may also be configured/transmitted whichis averaged over the RBs covered by a single RF. This is particularlyuseful if different RF supports different numerology.

(8) Bandwidth Adaptation

If bandwidth adaptation is achieved and the aggregated bandwidth issmaller than the maximum bandwidth covered by single RF, a UE maydeactivate other RFs other than the primary RF. In terms of bandwidthadaptation, based on the knowledge of UE RFs, the network may alsoindicate the required number of RFs and its intended center frequency.In other words, when bandwidth adaptation is applied, first, a UE may beactivated or deactivated with secondary RF (It may also be possible toactivate/deactivate third or fourth RF as well). In terms ofactivation/deactivation, MAC CE and/or RRC and/or dynamic signaling viaDCI or separate signaling may be used. Another approach is to leave thisup to UE implementation and no explicit activation/deactivation of RFprocedure is supported. Depending on monitoring bandwidth, a UE mayswitch off or on some of RFs. In this case, depending on UE capabilitysignaling on bandwidth, the network may determine the bandwidth that theUE can support/can be configured with.

Bandwidth adaptation may occur without knowing the details of RF layoutof the UE. In this case, maximum RF switching delay including retuningand activation/deactivation should be considered for bandwidthadaptation. Generally, if RF activation is required for bandwidthadaptation, it may also include code-start, which may require more thana few milliseconds. In this sense, it is desirable that the networkknows or explicitly indicate whether to deactivate RF or not. If dynamicadaptation is used, the UE may not turn on or off the RF. Alternatively,if a UE turns on the RF to increase RF, a UE may drop receiving somedata during the activation. Alternatively, when bandwidth adaptation isindicated, a UE may response with the required latency to support theoperation. Primary RF may not be turned off anytime, unless a UE is indiscontinuous reception (DRX) cycle.

For reducing bandwidth, one or more RFs may be deactivated. This may bedone via RRC or MAC CE or dynamic signaling. Further reduction ofbandwidth may be done within primary RF. In other words, smallerbandwidth adaptation within a RF may occur only within a primary RF.This procedure may be common between UEs with one or multiple RFs. Forincreasing bandwidth, at first, bandwidth may be increased withinprimary RF. When further increase is necessary, activation of one ormore RFs may be considered. When activating one or more RFs, a UE may beconfigured with the bandwidth monitored by each RF which may be equal toor smaller than UE RF bandwidth. For example, if a secondary RF supports200 MHz, the UE may be configured with only 100 MHz for data monitoring.Increasing/decreasing within primary RF may be done via dynamicsignaling, whereas increasing/decreasing of additional RF may be donevia MAC CE/RRC signaling.

(9) HARQ buffer may be shared between different RFs.

(10) RRM measurement

Unless otherwise noted/configured, RRM measurement may occur once forthe configured resource for the wideband carrier. Alternatively, RRMmeasurement may occur for each RF and different frequency region may beconfigured per each RF. Wideband measurement across multiple RF may alsobe considered and aggregated/average RRM measurement over multiple RFmay be reported, or separate/individual RRM measurement may be reportedper RF.

Alternatively, RRM may only be supported in primary RF. Primary RF mayperform RRM measurement on the serving cell, and secondary/multiple RFsmay be used for inter-frequency measurement. For serving cellmeasurement or connected measurement for intra-frequency measurement,frequency region may be used only for primary RF and the measurementbandwidth may be configured to equal to or smaller than the primary RFbandwidth.

(11) Fallback

If RF is activated or deactivated and one TB can be mapped over multipleRFs, during activation or deactivation, ambiguity may occur as thenetwork does not know when the UE is ready or finish the activation. Inthis case, if multiple RFs are utilized, primary RF may be assignedwhere the bandwidth for scheduling via CSS or group-common SS may befitted within the bandwidth supported by the primary RF. If primary RFbandwidth is changed, minimum bandwidth assumed not to be changed may beused for CSS scheduling. For example, a UE has two RFs with 100 MHzeach, and one RF may be defined as a primary RF. In this case, theresource allocation bandwidth via CSS for that UE may be equal to orsmaller than 100 MHz. In other words, at least one RF may always beactivated and fallback bandwidth may be smaller or equal to the primaryRF bandwidth. After DRX, only one RF may be activated, and monitoring oncontrol during On_duration may be limited to the bandwidth of one RF. Ifactivation/deactivation of RF is done via network indication, thebandwidth/PRBs where each RF is monitoring may be indicated. Further,the primary RF and its monitoring PRBs should be negotiated or informedto the network so that the network would not perform turning of all PRBsof the primary RF. Or, fallback message may be delivered to the primaryRF bandwidth.

(12) Tracking

Tracking RS may cover multiple RFs used by the UE. If tracking RS istransmitted in subband, multiple subband transmission may be used fortracking RS transmission so that each RF can acquire tracking RS fromeach monitored subband. However, different periodicity and/ortime/frequency resource may be used for tracking RS transmission indifferent bandwidth/subbands.

(13) Radio link failure (RLF)

RLF may be performed based on the total bandwidth supported by multipleRF. Or, RLF may be performed based only on primary RF. RLF may beperformed only within the bandwidth configured for control resource set.If multiple control resource sets are configured for one UE, theresource set where common search space or group common search space ismonitored may be used for RLF measurement. If only partial bandwidthwithin the control resource set is used for C/GSS, RLF may be furtherrestricted to such PRBs where C/GSS candidates can be mapped.

Different options of each functionality described above may beconfigured by the network via higher layer. Further, different mechanismbetween single carrier vs multiple carrier may be considered between DLand UL, respectively. In other words, a UE may support different RFbandwidth for DL and UL respectively, or even if a UE supportshomogeneous RF bandwidth for DL and UL, the configuration may bedifferent as the network maintains the system bandwidth differentlybetween DL and UL.

11. Emission Handling

When UL transmission is scheduled over multiple RFs, necessary emissionsshould be considered. If a UE performs transmission in the configuredRBs, it can have adjacent channel selectivity (ACS), in-band emission,and out-of-band emission. This issue may occur in both single RF withsmaller bandwidth than a system bandwidth either by bandwidth adaptationor by UE capability, and multiple RF where one scheduling may span morethan one RFs.

(1) Case 1: Small bandwidth transmission

FIG. 17 shows an example of interference in case of small bandwidthtransmission. Referring to FIG. 17, different bandwidth may lead highinterference from emission from other UEs, when different UEs areutilizing different portions of bandwidth within a system bandwidth.

To address this issue, the following mechanisms may be considered.

Based on network scheduling: The network may not schedule to createguard-band between two UEs. For example, UE2 may not be scheduled inPRBs where high interference from UE1 is expected. If RB level or RBGlevel indication is supported, scheduling indication may be sufficient.If contiguous resource allocation is used, explicit data rate matchingmay be indicated.

For explicit rate matching, various approaches may be considered. First,assuming guard-band size of K MHz in each side of transmissionbandwidth, rate matching for either one or both may be indicated. Thismechanism makes guard-band in the transmitter side by scheduling moreRBs than the required in consideration of guard band. Alternatively,whether to assume implicit guard-band within a transmission bandwidthmay be configured semi-statically. Instead of dynamic indication ofcreating guard-band, another example is to always create guard-bandwithin the allocated transmission bandwidth. This approach mayunnecessarily lead unused resource even if there is no adjacent PRBtransmission by another UE. Also, if a UE supports the system bandwidth,this may create additional unnecessary guard-band. To avoid such a case,system bandwidth may be mapped over the entire carrier bandwidthassuming no guard-band for UL transmission, and guard-band may beimplicitly created depending on UE capability. To successfully receivethe data, the network needs to know guard-band required for a UE.Alternatively, guard-band may be explicitly indicated by indicating thatone or more RBs are rate matched. By this mechanism, a UE may performrate matching on one or more RBs as if they are reserved resources.

Guard-bands may be configured per each subband. Assuming that ULbandwidth is divided into a set of subbands, guard-bands may beconfigured per each subband and a UE may assume no data mapping on thoseguard-bands regardless of configured bandwidth. One drawback of thisapproach is that depending on the configured bandwidth, the requiredguard-band may be different, and thus, depending on actual transmissionbandwidth, the configured guard-band may or may not be sufficient.

Different modulation and coding scheme (MCS) may be configured indifferent region by configuring separate region with MCS. As data mappedin PRBs which may be interfered by another UE, one approach is to mapdata with lower MCS or higher power. In other words, different MCS maybe configured in different PRBs or different power may be configured indifferent PRBs by scheduling.

PRACH transmission or PUCCH transmission should not be affected byguard-band of a UE. One approach is to configure PRACH, PUCCH resourcewhere any guard-band is not mapped. For example, if the network dividesthe system bandwidth into a set of subbands, and a UE's RF bandwidth isone or multiple of subbands, guard-bands may be created aroundboundaries of subband. Thus, PRACH and PUCCH resources may be configuredwithin a subband, i.e., by not passing through subband boundaries toavoid impacts from potential guard-band of another UEs. In terms ofPRACH/PUCCH resource configuration, the offset may be given per eachsubband. In other words, configuration may be given in {subband index,offset within a subband}. If two pairs of resources are necessary forPUCCH to allow frequency hopping, two sets of {subband index, offset}may be given, and the offset may be applied from the lowest frequencyfor lower subband index, and highest frequency for higher subband index.

(2) Case 2: Multiple RFs

FIG. 18 shows an example of interference in case of multiple RFs. Thatis, interference may be caused by another RF within the same UE iflarger bandwidth than the supported bandwidth by single RF is scheduled.

To address this issue, the following mechanisms may be considered.

A TB may not be mapped over bandwidth more than one RF's bandwidth. Inother words, to utilize larger bandwidth than single RF bandwidth, morethan one TBs may be used for the given UE.

A UE may assume that data is rate matched or punctured in the neededguard-band. The needed guard-band may be either specified in thespecification or signalled by the UE. In other words, effective RBs usedfor transmission may be restricted excluding the required guard-band. Ifa UE changes guard-band dynamically, a UE may indicate the usedguard-band in PUSCH transmission. Alternatively, the network mayindicate the guard-band usable for data transmission.

As it is difficult to assume or rate matching on PRACH and PUCCH, PRACHand/or PUCCH may not be scheduled over multiple RFs simultaneously. Itis possible that PUCCH is transmitted in one RF in one slot whereas inanother slot in another RF to realized frequency hopping. If PRACH orPUCCH is configured within the subband as mentioned above, this may beavoided by restricting UE bandwidth aligned with subband configuration.

Assuming that subband configuration is given and a UL bandwidth isconfigured with one or more subbands, it is also possible that thecenter of each subband may be potential DC carriers without explicitsignaling. In such center, DM-RS may not be mapped. To minimize impacton DFT-s OFDM transmission, the DC may always be the first or lastsubcarrier of each subband.

Techniques for the single RF case mentioned above may be applied tomultiple RFs case.

12. Handling Different Maximum RF Bandwidth UEs

If multiple RFs are used and the network employs wide system bandwidth,the following options may be considered for UE RF bandwidth.

(1) UE RF bandwidth may be fixed. For example, UE RF bandwidthsupporting multiple RFs to support wider bandwidth than the maximumbandwidth of a RF may be 100 MHz.

(2) UE RF bandwidth may have more than one candidate values, e.g. {50MHz, 100 MHz, 200 MHz}. For example, depending on UE capabilities, tosupport 400 MHz system bandwidth, some UE may require 8 RFs, some UEsmay require 4 RFs and some other UEs may require 2 RFs. However, RFbandwidth supporting intra-contiguous wideband may be common from a UEperspective.

(3) UE RF bandwidth may have more than one candidate values e.g. {50MHz, 100 MHz, 200 MHz}, and each UE may be equipped with multiple RFswith different bandwidth supported. For example, a UE may support 50MHz*2 RF and 100 MHz*1 RF and 200 MHz*1 RF.

Regardless of which options are considered, for better management, thecandidate RF bandwidth may be constructed in a nested manner, e.g. {MMHz, M*2 MHz, M*4 MHz . . . }. The idea is to construct minimum systembandwidth subband, and support different UE RF bandwidth by aggregatingmultiple minimum system bandwidth subbands.

For handling different RF bandwidth UEs, the following approaches may beconsidered.

(1) All UEs may be treated with equal priority so that all configurationare based on the minimum UE bandwidth. This may be applied to RRMmeasurement requirements, common or group common search space, neighbourcell measurement, RLF, etc. If this option is used, a UE supportinglarger bandwidth than the minimum bandwidth may achieve betterperformance compared to the minimum bandwidth UEs by reconfiguring RRMmeasurement bandwidth and/or other configurations.

(2) UEs with different bandwidth may be treated differently. Forexample, RRM measurement requirement may be different based on UEsupported bandwidth. For example, RRM measurement duration or therequired duration to report RRM measurement may be relaxed based on thesupported bandwidth. Overall RRM measurement requirement may be based onthe nominal bandwidth.

(3) Separate bandwidth or subbands may be allocated and one subband maybe allocated to UEs with the same RF bandwidth only.

(4) Overlaid structure in which different subbands are constructed basedon possible UE RF bandwidths may be configured. A UE may be assigned onesubband based on RF bandwidth.

FIG. 19 shows an example of overlaid structure according to anembodiment of the present invention. Referring to FIG. 19, the systembandwidth can be divided into different bandwidth subbands and each UEmay be configured with {bandwidth class, subband index}. Bandwidth classrefers to the bandwidth configured to the UE. For example, even if a UEsupports M MHz bandwidth, to support bandwidth adaptation of smallerbandwidth, it may be configured with M/2 or M/4 or M/8, etc. In otherwords, bandwidth adaptation may also occur based on the bandwidth classor supported bandwidths. Once bandwidth class is defined, the subbandaccording to the assigned bandwidth class may be configured, and a UEmay expect to receive control and/or data and/or RRM and/or RLFmeasurement. Resource allocation may also be done within that subband.If dynamic bandwidth adaptation can be achieved, resource allocation mayalso include {bandwidth class, subband index}. To minimize theambiguity, one approach is to allow multiple entries which may be mappedto multiple bandwidth class and subband indices. For example, if UEbandwidth candidates are M, M/2, M/4, M/8, M/16, M/32, one value ismapped to M, two values are mapped to M/2, four values are mapped toM/4, and so on, where total of 64 entries may be mapped to differentpairs of bandwidth class and subband index. Meanwhile, even though thesubband shown in FIG. 19 is constructed in a non-overlapped manner,overlapped subband structure may also be considered in which the numberof subband indices is increased.

If overlaid structure is used, search space candidate for CSS/GSS may beconstructed so that for M/8 bandwidth case, P/8 candidates are mapped ineach block/subband, and for M/4 bandwidth case, P/4 candidates aremapped in each block/subband, and so on. UEs supporting larger bandwidthmay have larger candidates and a UE monitors all or subset of candidateswhich may be further configurable. For CSS and GSS, separateconfiguration per purpose of search space may also be considered. CSSmay be configured within the minimum UE RF bandwidth frequency region,and GSS may be configured separately per each UE RF bandwidth for loadbalancing.

13. Handling Multiple RF via UE-Perspective CA

For supporting wider bandwidth than maximum bandwidth supported by oneRF, two approaches may be considered. One approach is to support onewideband carrier which can be realized by more than one RFs, and theother approach is to support multiple narrowband carriers and eachcarrier can be realized by multiple RFs. For the latter approach,further details are described above (10. Single data subband mappingwith multiple RF). Here, the former approach is mainly focused on, inwhich a UE may be configured with multiple carriers and each carriercorresponds to one RF. UE-carrier based approach may be more efficientat least if a UE may operate with different numerology in each RFcomponent.

In terms of carrier, the followings may be defined.

Though it may be configured to receive one TB over multiple carrier, asa baseline, a UE may expect that one TB is mapped within one carrier. Ifmultiple carriers are configured, a UE may expect to receive multipleTBs via multiple RFs.

Separate HARQ process may be performed in each carrier. The soft buffermay be divided over multiple HARQ processes across multiple RFs.

At least one control resource set may be expected per carrier, and a UEmay be configured with cross-carrier scheduling from one controlresource set to schedule another carrier. Cross-carrier scheduling maybe configured per each control resource set. In other words, even thougha UE is configured with cross-carrier scheduling, depending on controlresource set, cross-carrier scheduling and self-carrier scheduling maycoexist, and cross-carrier scheduling may be supported by subset ofcontrol resource sets. Also, search space candidates may be restrictedwithin control resource set for cross-carrier scheduling.

CSI feedback (and other feedback) may be reported per each carrier.Particularly, when wideband CQI is performed, independent wideband CQImay be performed within a carrier. Multiple wideband CQI may betransmitted when there are multiple RFs supporting multiple narrowband.

From UE perspective, single numerology may be assumed per carrier atleast for data transmission. Different numerology may be used forcontrol and other signals, such as synchronization signals.

To support the above description, the following approaches may beconsidered.

The network may configure multiple carriers and each carrier bandwidthmay be equal to or smaller than the UE maximum RF bandwidth. To minimizethe overhead, one or more carriers (contiguous intra-band carriers) mayomit synchronization signals, PBCH, and RRM measurement RS, SIB, etc.Though synchronization signals/PBCH/SIB may not be transmittedperiodically to support association as stand-alone cell, it may bepossible to transmit synchronization signals/PBCH/SIB (all or partial)to assist UE tracking and system information update. For PBCH and/or SIBtransmission, a UE may retune to anchor subband where synchronizationsignals/PBCH are transmitted, regardless of monitoring frequency band.During acquiring synchronization signals/PBCH, a UE may skip receivingdata or the UE receives/transmits control/data in the anchor subbandwhile the UE is on the anchor subband. It may also be configured as ameasurement gap to read synchronization signals and/or PBCH of theserving cell as well. Alternatively, if a UE monitors frequency bandincluding anchor subband, the UE may acquire system information in theanchor subband. Otherwise, a UE may request update of the systeminformation based on system update indication. Upon receiving therequest, the network may transmit periodic or aperiodic or UE-specificor group-specific PBCH and/or SIB. This approach does not require a UEto retune for PBCH/SIB acquisition. Alternatively, the network maytransmit PBCH/SIB in each subband upon SIB update so that all UEs canacquire PBCH/SIB without changing frequency location or separateoperation.

A UE may be aggregated with one or multiple carriers, similar to currentLTE CA.

Depending on UE bandwidth, within the same bandwidth or a set of PRBs,some UEs may be supported by single RF/single carrier whereas some UEsmay be supported by multiple RFs/multiple carriers. In this case, singleor multiple carriers may be configured to each UE from UE perspective.For a UE with multiple RF, it is handled as if multiple UEs with singleRF is supported from the network perspective.

14. RRM Handling in Wideband

When a UE is configured with UE-specific bandwidth, handling of RRMmeasurement may follow one or more of the following options.

(1) Option 1

FIG. 20 shows an example of option 1 for RRM handling in widebandaccording to an embodiment of the present invention. According to option1, measurement bandwidth follows UE-specific bandwidth and measurementbandwidth may be smaller or equal to UE-specific bandwidth. Ifmeasurement bandwidth is configured larger than UE-specific bandwidth, aUE may not be required to monitor or measure outside of its configuredbandwidth. For option 1, the followings may be considered.

To support wideband RRM or RRM outside of its currently configuredUE-specific bandwidth, one option is to configure multiple RRMconfigurations or separate RRM configuration per UE-specific bandwidth.

For each RRM configuration, periodicity and bandwidth of RRM measurementmay be configured. Following periodicity configuration, a UE may switchits UE-specific bandwidth. Necessary frequency retuning gap may be addedwhenever frequency retuning occurs.

One of drawback of this option is to utilize second RF for measurementoutside of configured UE-specific bandwidth. To measure differentbandwidth, separate UE-specific bandwidth for second RF may benecessary. Alternatively, this may be applied only within a RF. If a UEindicates additional RF or a UE is equipped with additional RF, RFmeasurement on different frequency/RRM bandwidth may be possible. Tosupport this, the network may configure a list of frequency where SSblock is transmitted and/or RRM-RS is transmitted. Alternatively, a listof frequency, bandwidth for RRM measurements may be configured to a UEif the network knows that the UE is equipped with additional RF.

When this option is used, measurement may occur on the same frequencyrange where control and data are also received. Whenever a UE switchesits frequency, its control resource set configuration and resourceallocation may be changed as well.

For L3-filter, separate RRM filter per UE-specific may be used, anddifferent RRM results (as if they are multiple carriers) may bemaintained. To determine whether to trigger any handover procedure, orinform the network, average value or best value or worst across multipleconfigurations may be selected. In this case, the selected value betweenneighbor cell and serving cell may be used for determiningevents/reports. Alternatively, when comparing results between servingcell and neighbor cell, the values from the same configuration may beused. To trigger event, it may follow either event is triggered at leastone configuration triggers event or all configurations trigger theevent. For example, if only one configuration shows that neighbor cell'squality is much better than that of serving cell, following the firstapproach, a UE may report its event. But following the second approach,a UE may not report its event.

(2) Option 2

FIG. 21 shows an example of option 2 for RRM handling in widebandaccording to an embodiment of the present invention. According to option2, a list of measurement bandwidth, frequency may be configuredindependently from UE-specific bandwidth. Whether a UE needs ameasurement gap for such measurement or not may be informed to thenetwork so that the network can configure necessary measurement gap. IfRRM measurement does not require retuning, measurement gap may beomitted. Depending on BWP configuration, necessary gap may be created bythe UE by not receiving/transmitting some control/data during the gap.

(3) Option 3

FIG. 22 shows an example of option 3 for RRM handling in widebandaccording to an embodiment of the present invention. According to option3, a configuration of measurement RS, such as CSI-RS, may be configuredlarger than UE-specific bandwidth. The measurement may be done withinUE-specific bandwidth based on bandwidth adaptation. However,measurement bandwidth may not exceed UE RF bandwidth. Additionalmeasurement utilizing second RF may also be performed based oninformation on the list of SS block or a list of RRM frequency,bandwidth. In terms of RRM measurement, L3-filter may be shared amongdifferent bandwidth. In other words, RRM result may be averagedregardless of actual bandwidth of measurement. Alternatively, it may benotified to higher layer to reset RRM measurement results wheneverbandwidth is changed. When this option is used, measurement on the samefrequency location regardless of BWP change may be accumulated.

(4) Option 4: RRM measurement may occur on the smallest UE-specificbandwidth which may not be changed regardless of actual bandwidthadaptation.

RRM measurement on neighbor cell may be same as serving cell. Or, RRMmeasurement on neighbor cell may be separate from serving cell.

Meanwhile, when a UE changes its bandwidth, the following two approachesmay be considered for RRM bandwidth.

(1) Independent configuration from BWP: Measurement bandwidth may beconfigured which is smaller or equal to UE RF bandwidth. If thisapproach is used, whenever a UE needs to perform measurement and thebandwidth may be larger than its currently configured BWP, the UE maychange its RF bandwidth. When measurement is configured, periodicity andbandwidth of measurement RS may be configured.

(2) Dependent configuration on BWP: RRM measurement may be done withinUE-configured frequency range (BWP) at a given time. Whenever aUE-configured frequency range changes, RRM measurement at L3-filter maybe reset (if the measurement bandwidth or location is changed).

FIG. 23 shows an example of different RRM bandwidth options according toan embodiment of the present invention. FIG. 23-(a) shows an independentconfiguration from BWP, and FIG. 23-(b) shows a dependent configurationon BWP. Meanwhile, further considerations including RRM requirements maybe considered to select between two category options.

When a UE is equipped with multiple RFs, before configuring additionalUE-specific carrier, a UE may need to perform RRM measurement onfrequency range outside of its currently active bandwidth within a NRcarrier bandwidth. The potential benefit of RRM measurement on differentfrequency range in a NR carrier is that due to different interferencelevel, a UE can search better frequency range among multiple candidates.For this, a UE may be configured with measurement configurations outsideof its active bandwidth. Generally, this may also be supported fornarrowband UEs with single RF, which may be done via measurement gapconfiguration or bandwidth adaptation.

15. CSI Handling in Wideband

In CSI feedback, at least wideband and subband CSI feedback may beconsidered. In terms of frequency bandwidth and location for widebandCSI, similar options to RRM handling may be considered.

(1) Option 1: Separate frequency and bandwidth information may beconfigured for wideband CSI feedback per UE-specific bandwidth. In termsof wideband CSI, average across CSI measurement based on the sameUE-specific bandwidth or the same configuration may be assumed.

(2) Option 2: Wideband CSI bandwidth may be configured which may requiresome gap to perform measurement.

(3) Option 3: Wideband CSI may always be measured within UE-specificbandwidth. Wideband CSI results may be reset whenever a UE changes itsbandwidth. Further, wideband CSI results may be averaged regardless ofactual bandwidth.

For subband CSI, the following two approaches may be considered. Oneapproach is to follow UE-specific bandwidth as a whole, then dividesubband based on UE-specific bandwidth. The other approach is to followsystem bandwidth as a whole, then divide subband based on systembandwidth.

If Option 1 is used and multiple CSI configurations are possibleincluding potentially different bandwidth and frequency location,aperiodic CSI trigger may trigger one of CSI configurations. Whenaperiodic CSI is triggered outside of its current UE-specific bandwidth,a UE may adapt its bandwidth before CSI measurement. When Option 3 isused, CSI measurement may follow UE-specific bandwidth.

Similar to RRM measurement bandwidth, some clarification on wideband CSIfeedback may be necessary. As the periodicity of CSI measurement isgenerally shorter than RRM measurement, it may not be efficient toconfigure separate configuration for wideband CSI feedback independentfrom BWP. As wideband CSI is mainly for data scheduling, it is generallydesirable to align wideband CSI feedback bandwidth with the configuredBWP. In other words, bandwidth of wideband CSI may be defined same asthe UE BWP for UE-specific data. When UE BWP is changed, wideband CSImeasurements may be reset. For subband CSI, it may be defined within itsconfigured BWP.

For aperiodic CSI report or one-shot CSI report, to allow possiblefrequency retuning to better frequency for frequency selectivescheduling, frequency location of CSI measurement may be indicated. Ifthis is configured, necessary frequency retuning gap should besupported.

When BWP changes, for CSI measurement, if the measurement is accumulatedper subband, this requires ‘no’ change or ‘nested’ structure of subbandchange so that previous measurement on a subband can be used for anothersubband in changed BWP.

It is also noted that similar approach to RRM or CSI may also be appliedto radio link management (RLM) measurement. For example, RLM measurementmay be performed within the configured data subband or control subbandand average may be applied across different data or control subbands.

FIG. 24 shows a method for configuring a data subband by a UE accordingto an embodiment of the present invention. The present described abovemay be applied to this embodiment.

In step S100, the UE receives an indication of a data subband from anetwork. In step S110, the UE configures at least one data subbandaccording to the indication. In step S120, the UE performs communicationwith the network via the at least one data subband. One data subbandconsists of contiguous or non-contiguous PRBs.

At least one of a numerology used for data transmission, a slot length,a mini-slot length, a RAT or a maximum TBS may be defined per datasubband. The at least one data subband may be configured in aUE-specific carrier. The UE-specific carrier may be configured per RF.The at least one data subband may be configured across multipleUE-specific carriers. The data subband may include a common data subbandfor a common data. At most one common data subband may be configured forthe common data.

The at least one data subband may be scheduled by a control subband. Atleast one of a numerology used for control transmission, a monitoringinterval or REG/CCE index within the control subband may be defined percontrol subband. The control subband may be configured in an anchorsubband.

A number of PRBs within a UE supported bandwidth may be used forresource allocation of the at least one data subband. Or, a maximumnumber of PRBs configured to the data subband may be used for resourceallocation of the at least one data subband.

The UE may further perform RRM measurement on one or multiple subbandswhen the network configures one wideband carrier. In this case eachsubband may carry a SS block. Or, only anchor subband may carry a SSblock. Alternatively, the UE may perform RRM measurement on one ormultiple carriers when the network configures multiple narrowbandcarriers.

FIG. 25 shows a wireless communication system to implement an embodimentof the present invention.

A network node 800 includes a processor 810, a memory 820 and atransceiver 830. The processor 810 may be configured to implementproposed functions, procedures and/or methods described in thisdescription. Layers of the radio interface protocol may be implementedin the processor 810. The memory 820 is operatively coupled with theprocessor 810 and stores a variety of information to operate theprocessor 810. The transceiver 830 is operatively coupled with theprocessor 810, and transmits and/or receives a radio signal.

A UE 900 includes a processor 910, a memory 920 and a transceiver 930.The processor 910 may be configured to implement proposed functions,procedures and/or methods described in this description. Layers of theradio interface protocol may be implemented in the processor 910. Thememory 920 is operatively coupled with the processor 910 and stores avariety of information to operate the processor 910. The transceiver 930is operatively coupled with the processor 910, and transmits and/orreceives a radio signal.

The processors 810, 910 may include application-specific integratedcircuit (ASIC), other chipset, logic circuit and/or data processingdevice. The memories 820, 920 may include read-only memory (ROM), randomaccess memory (RAM), flash memory, memory card, storage medium and/orother storage device. The transceivers 830, 930 may include basebandcircuitry to process radio frequency signals. When the embodiments areimplemented in software, the techniques described herein can beimplemented with modules (e.g., procedures, functions, and so on) thatperform the functions described herein. The modules can be stored inmemories 820, 920 and executed by processors 810, 910. The memories 820,920 can be implemented within the processors 810, 910 or external to theprocessors 810, 910 in which case those can be communicatively coupledto the processors 810, 910 via various means as is known in the art.

In view of the exemplary systems described herein, methodologies thatmay be implemented in accordance with the disclosed subject matter havebeen described with reference to several flow diagrams. While forpurposed of simplicity, the methodologies are shown and described as aseries of steps or blocks, it is to be understood and appreciated thatthe claimed subject matter is not limited by the order of the steps orblocks, as some steps may occur in different orders or concurrently withother steps from what is depicted and described herein. Moreover, oneskilled in the art would understand that the steps illustrated in theflow diagram are not exclusive and other steps may be included or one ormore of the steps in the example flow diagram may be deleted withoutaffecting the scope of the present disclosure.

1. A method for configuring a data subband by a user equipment (UE) in awireless communication system, the method comprising: receiving aconfiguration of a plurality of data subbands from a network; receivinga first scheduling downlink control information (DCI) includinginformation on a first data subband among the plurality of datasubbands; activating the first data subband; receiving a secondscheduling DCI including information on a second data subband among theplurality of data subbands; performing a bandwidth adaptation from thefirst data subband to the second data subband; and activating the seconddata subband, wherein one data subband consists of contiguous ornon-contiguous physical resource blocks (PRBs).
 2. The method of claim1, wherein at least one of a numerology used for data transmission, aslot length, a mini-slot length, a radio access technology (RAT) or amaximum transport block size (TBS) is defined per data subband among theplurality of data subbands.
 3. The method of claim 1, wherein at leastone of the first data subband or the second data subband is configuredin a UE-specific carrier.
 4. The method of claim 3, wherein theUE-specific carrier is configured per radio frequency (RF).
 5. Themethod of claim 1, wherein at least one of the first data subband or thesecond data subband is configured across multiple UE-specific carriers.6. The method of claim 1, wherein at least one of the first data subbandor the second data subband includes a common data subband for a commondata.
 7. The method of claim 6, wherein at most one common data subbandis configured for the common data.
 8. The method of claim 1, wherein atleast one of the first data subband or the second data subband isscheduled by a control subband.
 9. The method of claim 8, wherein atleast one of a numerology used for control transmission, a monitoringinterval or a resource element group (REG) or control channel element(CCE) index within the control subband is defined per control subband.10. The method of claim 8, wherein the control subband is configured inan anchor subband.
 11. The method of claim 1, further comprisingperforming channel state information (CSI) measurement within at leastone the first data subband or the second data subband.
 12. The method ofclaim 1, further comprising transmitting a sounding reference signal(SRS) within at least one the first data subband or the second datasubband.
 13. The method of claim 1, further comprising performingmeasurement on a frequency which is configured independently from thefirst data subband and the second data subband.
 14. The method of claim13, wherein the frequency carries a synchronization signal (SS) block.15. (canceled)
 16. (canceled)
 17. A user equipment (UE) in a wirelesscommunication system, the UE comprising: a memory; a transceiver; and aprocessor, operably coupled to the memory and the transceiver, that:controls the transceiver to receive a configuration of a plurality ofdata subbands from a network, controls the transceiver to receive afirst scheduling downlink control information (DCI) includinginformation on a first data subband among the plurality of datasubbands, activates the first data subband, controls the transceiver toreceive a second scheduling DCI including information on a second datasubband among the plurality of data subbands, performs a bandwidthadaptation from the first data subband to the second data subband, andactivates the second data subband, wherein one data subband consists ofcontiguous or non-contiguous physical resource blocks (PRBs).